Plasmashell periodically freezing

[Bug Reporter <bugreporter11@xxxxxxxxx>]

In the last two days Plasmashell has started freezing every hour or so.

QMake version 3.1
Using Qt version 5.11.0 in /usr/lib
plasmashell 5.12.5
Linux laptop 4.16.12-1-ARCH #1 SMP PREEMPT Fri May 25 23:30:31 UTC 2018 x86_64 GNU/Linux

I can recover with these commands:

killall plasmashell
plasmashell > /dev/null 2>&1 & disown

How should I debug this? I don't see anything relevant in the systemd journal.

The only thing I have done recently that might be related to this is that by mistake I ran the following command:

chmod -R 770 /home/

To attempt to fix that, I went through and reset permissions like this:

find /home -mount -type f -exec chmod 660 {} \;
chmod 644 /home/*./.bash*
chmod 600 /home/*./.bash_history
chmod 700 /home/*/.ssh
find /home/*/.ssh -mount -type f -exec chmod 600 {} \;

Could the Plasma freezing be related to file permissions in /home? If so, which permissions do I need to check / fix?