In 5.17.4, images that were marked as "position relative to paragraph" maintained their position even if brought into a WPRichtext via a mailmerge.
However, since then (5.18.6 and even the brand new 5.18.7, maybe earlier versions too), those images get aligned at the beginning of the paragraph after the mailmerge.
I had also used 5.18.3, but not sure if the problem was in that version or not... I can backtrack if you'd like me to.
This is critical!!!! I wish I noticed this two weeks ago!