Freeze while navigating external storage folders

[jmfarina]

Nextcloud 13.0.1
W2G2 2.0.5
MySQL 5.7

We have an external storage enabled, and after navigating the folders for a while(*), Nextcloud freezes completely and the MySQL process CPU usage spikes. Only way I found to make it responsive again is to restart MySQL service.

• No error or indication in nextcloud or mysql logs.
• Command `sudo -u www-data php /path/to/nextcloud/occ files:scan user*name' didn't report any errors whatsoever and completed immediately.
• This only happend with external storages, either mounted locally (as a folder in the file system) or as an external storage in Nextcloud.
• It seems to work just fine with local folders.
• External storage didn't present any problems navigating it otherwise (from API/another client/command line).
• Disabled W2G2 and it works properly. Just to make sure, we enabled it once more and the problem re-appeared right away.

(*) oddly as it sounds, it seems to happen after the third folder you open, whichever that is, within that external storage, and regardless of the amount of files/subfolders it contains.