The reverse seems to be true (room temp eggs not cracking well after cooling), so temp does something - I had some eggs sitting at room temp for a couple days (trying a different preserving method), and used a couple at room temp - not much different from normal eggs, maybe a bit less brittle. A couple others that didn't get used went back in the fridge afterwards. When I went to crack them today - they would not crack cleanly at all, the membrane had to be torn by hand to separate the cracked shell and it still came away in chunks rather than clean halves like I usually get (leaving aside "correct" cracking method, mine is consistent and got different results this time). The white was also much more gelatinous, and stuck more firmly to the inside of the shell and had to be scraped off.
Possibly the difference might come from the change in temp, several times. Maybe the speed of cooling was to blame for the difference (I imagine eggs cool quicker in the fridge than they warm at room temp). If so, a fridge-temp egg that was warmed too quickly might show the same problems. Or an egg that had been stored inconsistently in the past, allowed to cool and warm several times. Or, less plausibly the egg might, ah, adjust to the new temp after a while (so a few hours to days after a temp change are tricky, several days after either way is fine). That could account for why someone might find warming an egg to room temp, harder to crack.
For myself, I can only say the warmer eggs didn't give me any problem - they were a bit less brittle, which meant a tapping out a cleaner break rather than the shell shattering or chipping under the force, and a bit easier to crack (less force to get the cracking started).