Thermal pads do dry out, it's dependent on frequency of the thermal cycles they're put through, storage conditions, or just manufacturing defects within a certain batch. If this freezing phenomenon started happening after the first laser replacement I'd ask if the tech pulled the heatsink plate at all and put it back with a ripped pad or could have neglected to check and see if any had fallen out of position. This is just a guess as I don't have the console in front of me to look at it (and I don't want to see it, I'm not soliciting a job here. )
That the system struggles to operate after a freeze and immediate reset or power cycle suggests that it was still in an overheated state and wanted to cool back down.