JK wrote:
> If a bottle's cork is slightly pushed out does that always mean the wine is
> heat damaged or could there be another explanation?

It's likely it's been through some temperature change (although, it's
possible that it was subjected to cold rather than heat). Damage is
always a possiblity, but it's also possible for it to be OK, and it's
possible for heat damange to occur with a normal looking cork.