Can speed bumps knock out engine bolts/mounts?

Dear Mechanics,

My friend has a 2010 Citroen Nemo.

She had some issues with the engine bolts in the past.

The local mechanic said he fixed it.

Recently after going over speed bump, 3 failed. After that car wouldn't start (grinding noise).

The mechanic (who fixed it last time) reckons it was the speed bump.

Is that even possible if the repair jobs was done properly? I only saw one of the bots and it was snapped cleanly into two pieces.

Advice welcome !