The Rails bundle uses ⌃p for its params snippet, which drives me insane... everywhere else ⌃p means "up one line". When I change it to a tab trigger (and type "para"), the change won't stick. If I move to another bundle item and back, the activation type is back to "Key Equivalent". If I change it to "Tab Trigger" again, "para" shows up, but again the change doesn't stay.
The only way I've found to work around this is remove the params snippet.