When you swallow an ally, and that ally then gets teleported, they should automatically get ejected. This goes for Chen's Teleport, Io's Relocate (both ways), and Underlord's Dark Portal.

What happens right now is, the ally does get teleported normally, but are still fully affected by Dismember, except that they are now located where they got teleported, and are no longer moved along with Pudge. So if you cast Eject, the ally appears at the teleport location.

PS: And please don't make it like the last time you did for Lifestealer's Assimilate. Don't code in custom interactions with the different teleport spells. Instead, make the Swallow modifiers get destroyed as soon as the movement gets interrupted by anything. Make the fix future-proof.