So, coming back after another couple of weeks, I had a crash on one switch after approx. 7 weeks of uptime. The crash happened when I tried to access the web interface. It seems to me that crash is highly related to accessing the web interface. My co...

uptime is 4 weeks, 5 days, 8 hours, and 12 minutes

Everything is working smoothly with the 15(7) E3. No crashes or any trouble so far.

Will do. I did set a reminder to check and report back here

Thank you for the hint. downgrading to 15.2(7)E3 indeed keeps the Cat1000 switch stable - at least so far, which would have crashed by now compared to the the k rebuild.