I don't know exactly when this happened, but since I started noticing it after update it could be 2020.2.1 issue.
If you press enter in the end of the statement, and then undo, re# will add as many spaces as in the indentation
I was in the end of line 85 and pressed Enter. Now cursor is at right position, if I press Ctrl-Z it doesn't jump to the end of line 85, it adds spaces:
(red arrow is mine)
If I do it on the C++ file which is not indexed by Re# it works fine, e.g. no spaces are added.
(JetBrains ReSharper 2020.2.1 Build 202.0.20200820.125348 built on 2020-08-20
ReSharper C++ 2020.2.20200820.145616