This is a two-part issue, so let's break it down.
Issue 1, the downtime rotation is processed all at once and can queue up multiple buffs.
The general idea here would be to adjust the delay before we will buff after moving (I believe the exact setting is BuffWaitMoveTimer, but I'm away from my PC), but it is admittedly imperfect.
Issue 2, every spell should be checking to ensure you aren't moving beforehand (at least, that is the case in class configs I've personally touched). However, if it does pass that check once, and the PC moves (thereby interrupting), the code to attempt a recast takes over and will do its thing.
I have definitely experienced what you are describing, sometimes I just want to go; and these buttheads can buff when the hell I get there...
Conversely, my own impatience comes into play here, and if I wait a couple of seconds, all is well. Anticipating rebuff (or learning/ understanding which class will do which thing when) can help alleviate this.
No slam-dunk fix here, as the queued rotation and attempted recasts help us elsewhere.
However, it seems reasonable to err a little more on the side of caution and reduce these situations.
I would like to see what some other people think and maybe do some playtesting with some tweaks when I am able (and I may not be immediately).
We could perhaps adjust how downtime processes or reduce the default reattempts.
Open to feedback definitely!