Hmm... Does it switch your weapon away with the auto-weapon switch turned on? If so, I would go into options -> player options and turn auto switch to off for the time being.
As for our end, the simplest way to resolve this is to perform a check like it already does and to exclude bunnies from spawning in said portal mode.
"well, im not too sure. I mean, we made money, but im not able to wipe my ass with $100 bills yet." - DBThanatos
"And one for Bobo the Space Monkey!" - Postal Dude
"My grandmother could beat the game if she saved as much as you do!" - Postal Dude
"Float... They aaaaaall float! And when you're down here with me, fat boy! YOU... float... too!" - Pennywise, the Dancing Clown
"In Offline Gaming We Trust" - DBT & MC
"That truck is fucked." - FPS Russia
Spetsnaz. When the only way to kill a terrorist is with a back-flipping Apache attack.