It seems that when playing a Rich Text Block into a Retainer Box, it causes the text inside the yellow row style to have additional spaces added to it. The user who reported this issue also had issues with the text clumping together into unintelligible text, but I wasn't able to get that result. Perhaps due to screen size or resolution.
I've uploaded what the text looks like in 4.26 and what it looks like in 4.25. Also, there's a test project to examine if you don't want to go through the repro steps: [Link Removed]
This was tested in //UE4/Release-4.25 @ CL 14469661 and this did NOT occur, so marking as a Regression.
Rich Text has incorrect spacing when placed inside a Retainer Box
The text would have the correct spacing when placed inside a Retainer Box
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-107863 in the post.