My proflite has a puke tank, well more of a recovery tank as it feeds from the bottom so anything that does get in it just goes back in to the trans later. It is from heat with heat the fluid expands a fair amount. As suggested drop the level a tad and for peace of mind use a puke or recovery tank. As for converter slip causing it sure that puts more heat in the fluid. Which will cause it to expand.

FWIW we use these. I use a vent on top and the line feeds from the bottom. Airlines work just fine with pushlock fittings.

https://quartermax.com/transmission-overflow-kit/