Don’t Convert to R134a

I tried envirosafe in my Dakota.

I got one can in and was monitoring the low side pressure and temp at the vents.

Just as it started to cool down inside.

braaaap, whooosh...

It expelled all that out the high side port.

Never seen anything like it.
What could cause the schrader valve to open from the internal side?
How did it know to expel only the envirosafe?
Back to where it was before I started.
Put in a can on 134 and temp came down to what's "normal" for that truck.

Proof Chryslers have "personalities" ?