Thanks for sending the file. After looking at it and discussing it with the developer who implemented the positioning of tempos and rehearsal marks, I can at least tell you what’s going on. In simple terms, the gradual tempo starting on the previous system, the rehearsal mark, and the immediate tempo following the rehearsal mark are positioned together. The playing technique in the following bar then causes the immediate tempo to move up, and the gradual tempo is also moved up to match, but because rehearsal marks and tempos are not the same kind of item, the rehearsal mark positioner doesn’t get a second bite of the cherry, so the rehearsal mark stays put. This is working as designed for the moment.