As others in the thread have mentioned it gets annoying when one party member just gives up crossing over.
Here’s a neat trick to get them over without selecting them (turn based or ungrouping first etc) -
While having the same character selected (the one that you jumped over), Toggle G (Ungroup) and quickly regroup again. This will reactivate the pathing for the left behind member.
Just make sure you are relatively close to the jumping point though. Also doesn’t work if there are two consecutive jumps between you and the separated member