MathML buildup broken when editing an equation and adding parenthesis

[MicrosoftIssueBot]

Summary
Rich editing for exponents becomes broken following a close parenthesis when parentheses are added later while input an equation

Repro Steps

1. Launch calculator in graphing mode.
2. In a function data entry field, start to input an equation such as: x^2+y^2−1. To input an exponent: press [Shift] + [6] > press exponent number of choice > then press spacebar
3. Add an open parenthesis in front of the x: (x2+y2−1
4. Add a closed parenthesis in behind the 1: (x2+y2−1)
5. Add an exponent to closed parenthesis
6. Observe the exponent

Observed results
The rich text edited version of the exponent is not added to the closed parenthesis. As the function is written out more, the rich text version any additional exponents is broken as well.
E.g. (x2+y2−1)^3 -x^2 y^3 = 0

Expected results
E.g.

Note
Exponents might be a red herring. I think it has to do with the adding parenthesis after the fact

[MicrosoftIssueBot]

This is your friendly Microsoft Issue Bot. I created this issue automatically as requested by a team member.