Spurious Core 0 "Guru Meditation" errors on L01 with firmware v1.8.0.b1

[Eric24]

I have two L01's, running v1.8.0.b1 firmware, mounted on the OEM reference board. Both work when initially powered up. After some period of time (from a few hours to a couple of days), while sitting idle at the REPL prompt (connected via PuTTY), a cascade of spurious error occurs. At first, I thought that one of the two L01's was defective, but I have now seen the same problem on both of them. I've seen several different error sequences, and none with similar backtraces, so I'm not sure how to go about figuring out what's happening here. I've attached three files, error logs from three difference instances of the failure.

I'm not sure if it's related, but doing a gc.mem_free() periodically from the REPL prompt showed slowly decreasing free memory, even though nothing was running on the L01.

What to do next?

Links to error logs:

• https://www.dropbox.com/s/fnwkwbnjxdjmajg/error1.txt?dl=0
• https://www.dropbox.com/s/ednlad7f7fxps0h/error2.txt?dl=0
• https://www.dropbox.com/s/2ve1299c6hytpga/error3.txt?dl=0

[Eric24]

Note: This error continues to happen at various intervals. The error logs are similar, but never identical.