diff --git a/.circleci/images/primary/Dockerfile-jruby-9.2.21.0 b/.circleci/images/primary/Dockerfile-jruby-9.2.21.0
index 6151a2a891d..d9e26b7aa0d 100644
--- a/.circleci/images/primary/Dockerfile-jruby-9.2.21.0
+++ b/.circleci/images/primary/Dockerfile-jruby-9.2.21.0
@@ -1,3 +1,12 @@
+# Note:
+#
+# There is an incompatibility between ethon and httprb on debian 11 bullseye.
+# This is why this image is based on debian 10 buster.
+#
+# See:
+# - https://github.com/jruby/jruby/issues/7033
+# - https://github.com/DataDog/dd-trace-rb/pull/2380#issuecomment-1320994823
+#
 # openjdk:8-jre image is from https://github.com/docker-library/openjdk/blob/a0c4da867ddd1a11408b7ec5032f12130bdc5476/8/jre/buster/Dockerfile
 # note: docker-library/openjdk is deprecated, there is a later move to https://hub.docker.com/_/eclipse-temurin
 FROM openjdk:8-jre-buster AS jruby-9.2.21.0-jre8
diff --git a/.circleci/images/primary/Dockerfile-jruby-9.2.8.0 b/.circleci/images/primary/Dockerfile-jruby-9.2.8.0
index 0cc276dca1e..fb02911596e 100644
--- a/.circleci/images/primary/Dockerfile-jruby-9.2.8.0
+++ b/.circleci/images/primary/Dockerfile-jruby-9.2.8.0
@@ -1,3 +1,12 @@
+# Note:
+#
+# There is an incompatibility between ethon and httprb on debian 11 bullseye.
+# This is why this image is based on debian 10 buster.
+#
+# See:
+# - https://github.com/jruby/jruby/issues/7033
+# - https://github.com/DataDog/dd-trace-rb/pull/2380#issuecomment-1320994823
+#
 # taken from https://github.com/jruby/docker-jruby/blob/5de2f8fd4c518cfb621be236fe7e9732c77b6129/9000/jre/Dockerfile
 #
 # openjdk:8-jre image is from https://github.com/docker-library/openjdk/blob/a0c4da867ddd1a11408b7ec5032f12130bdc5476/8/jre/bullseye/Dockerfile
diff --git a/.circleci/images/primary/Dockerfile-jruby-9.3.9.0 b/.circleci/images/primary/Dockerfile-jruby-9.3.9.0
index fe3ad3e19bb..cf657c938c5 100644
--- a/.circleci/images/primary/Dockerfile-jruby-9.3.9.0
+++ b/.circleci/images/primary/Dockerfile-jruby-9.3.9.0
@@ -1,3 +1,12 @@
+# Note:
+#
+# There is an incompatibility between ethon and httprb on debian 11 bullseye.
+# This is why this image is based on debian 10 buster.
+#
+# See:
+# - https://github.com/jruby/jruby/issues/7033
+# - https://github.com/DataDog/dd-trace-rb/pull/2380#issuecomment-1320994823
+#
 # openjdk:11-jre image is from https://github.com/docker-library/openjdk/blob/8dfb0c5645098b8c330c4811c8228cae52f18388/11/jre/buster/Dockerfile
 # note: docker-library/openjdk is deprecated, there is a later move to https://hub.docker.com/_/eclipse-temurin
 FROM openjdk:11-jre-buster AS jruby-9.3.9.0-jre11