diff --git a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/LegacyColumns.scala b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/LegacyColumns.scala
index 183ac088..06d85d60 100644
--- a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/LegacyColumns.scala
+++ b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/LegacyColumns.scala
@@ -125,8 +125,8 @@ object LegacyColumns {
               case TabledEntity.Context       => LegacyMode.Repeated
             }
             val columnName  = legacyColumnName(entityType, schemaKey)
-            val legacyField = LegacyField.build(columnName, schema, false).setMode(mode).normalized
-            val v2Field     = legacyFieldToV2Field(legacyField).copy(accessors = Set.empty)
+            val legacyField = LegacyField.build(columnName, schema, false).setMode(mode)
+            val v2Field     = V2Field.normalize(legacyFieldToV2Field(legacyField)).copy(accessors = Set.empty)
             FieldForEntity(v2Field, schemaKey, entityType)
           }
           .leftMap(ColumnFailure(schemaKey, entityType, _))
@@ -160,6 +160,24 @@ object LegacyColumns {
         BadRow.LoaderIgluError(processor, BadRowFailure.LoaderIgluErrors(nel), BadPayload.LoaderPayload(event))
       }.toEither
 
+  /**
+   * Replaces any Json type with a String type
+   *
+   * This must be run after transformation, but before handling schema evolution. It is needed
+   * because the legacy loader used String columns where the v2 loader would create Json columns
+   */
+  def dropJsonTypes(v2Field: V2Field): V2Field = {
+    def dropFromType(t: V2Type): V2Type = t match {
+      case V2Type.Json                        => V2Type.String
+      case V2Type.Array(element, nullability) => V2Type.Array(dropFromType(element), nullability)
+      case V2Type.Struct(fields)              => V2Type.Struct(fields.map(dropJsonTypes))
+      case other                              => other
+    }
+
+    v2Field.copy(fieldType = dropFromType(v2Field.fieldType))
+
+  }
+
   /**
    * Convert from the legacy Field of the old v1 loader into the new style Field.
    *
diff --git a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Processing.scala b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Processing.scala
index 8646f2f0..2182d19c 100644
--- a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Processing.scala
+++ b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Processing.scala
@@ -153,7 +153,7 @@ object Processing {
         (moreBad, rows) <- transformBatch[F](badProcessor, loadTstamp, events, v2NonAtomicFields, legacyFields)
         fields = v2NonAtomicFields.fields.flatMap { tte =>
                    tte.mergedField :: tte.recoveries.map(_._2)
-                 } ++ legacyFields.fields.map(_.field)
+                 } ++ legacyFields.fields.map(f => LegacyColumns.dropJsonTypes(f.field))
       } yield BatchAfterTransform(
         rows,
         fields,
diff --git a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Writer.scala b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Writer.scala
index f4720788..c9d14282 100644
--- a/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Writer.scala
+++ b/modules/core/src/main/scala/com.snowplowanalytics.snowplow.bigquery/processing/Writer.scala
@@ -8,7 +8,6 @@
  */
 package com.snowplowanalytics.snowplow.bigquery.processing
 
-import cats.Applicative
 import cats.implicits._
 import cats.effect.{Async, Poll, Resource, Sync}
 import com.google.api.gax.batching.FlowControlSettings
@@ -166,25 +165,20 @@ object Writer {
       def write(rows: List[Map[String, AnyRef]]): F[WriteResult] =
         Sync[F]
           .delay(writer.append(new JSONArray(rows.map(_.asJava).asJava)))
-          .attemptNarrow[BQExceptions.AppendSerializationError]
-          .flatMap[WriteResult] {
-            case Right(fut) =>
-              FutureInterop
-                .fromFuture(fut)
-                .as[WriteResult](WriteResult.Success)
-                .recover {
-                  case e: BQExceptions.SchemaMismatchedException =>
-                    WriteResult.ServerSideSchemaMismatch(e)
-                  case e: BQExceptions.StreamWriterClosedException =>
-                    WriteResult.WriterWasClosedByEarlierError(e)
-                }
-            case Left(appendSerializationError) =>
-              Applicative[F].pure {
-                WriteResult.SerializationFailures {
-                  appendSerializationError.getRowIndexToErrorMessage.asScala.map { case (i, cause) =>
-                    i.toInt -> cause
-                  }.toMap
-                }
+          .flatMap(FutureInterop.fromFuture(_))
+          .as[WriteResult](WriteResult.Success)
+          .recover {
+            // Some of these errors can happen either client side during `writer.append`
+            // ...or server-side during `FutureInterop.fromFuture(_)`
+            case e: BQExceptions.SchemaMismatchedException =>
+              WriteResult.ServerSideSchemaMismatch(e)
+            case e: BQExceptions.StreamWriterClosedException =>
+              WriteResult.WriterWasClosedByEarlierError(e)
+            case e: BQExceptions.AppendSerializationError =>
+              WriteResult.SerializationFailures {
+                e.getRowIndexToErrorMessage.asScala.map { case (i, cause) =>
+                  i.toInt -> cause
+                }.toMap
               }
           }