Pyrex under grill

[Dappymummy]

Just melting some cheese on mashed potatoe under the grill. I have put it in a Pyrex dish under the grill. Heard a slight bang sound but inspected the dish and it looked fine so decided it was the grill heating up. Now when washed up the fish I noticed a slight chip on the lip of the glass. Husband said it looks it was probably done in the dishwasher and couldn't been done by grill. Am I not supposed to put Pyrex under grill?

I don't think they are supposed to be exposed to direct heat e.g. on the hob or under the grill

Pyrex are heat proof and should be OK under the grill. What they don't like however is sudden changes in temperature eg. going from fridge to grill. Do that and any weaknesses in the glass can crack.