I saw my error log is full of warnings coming from the move plugin:
[Sat Jan 16 19:17:26.148433 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'origin' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 61, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148472 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Cannot assign an empty string to a string offset in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 61, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148479 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'pages' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 64, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148484 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'media' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 67, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148490 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'pages' in /home/star_army/stararmy/wiki/lib/plugins/move/action/rewrite.php on line 102, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148495 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'origin' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 61, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148506 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Cannot assign an empty string to a string offset in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 61, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148512 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'pages' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 64, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148517 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'media' in /home/star_army/stararmy/wiki/lib/plugins/move/helper/rewrite.php on line 67, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
[Sat Jan 16 19:17:26.148522 2021] [fcgid:warn] [pid 7235:tid 140560362882816] [client XXXXXX] mod_fcgid: stderr: PHP Warning: Illegal string offset 'pages' in /home/star_army/stararmy/wiki/lib/plugins/move/action/rewrite.php on line 102, referer: https://stararmy.com/wiki/doku.php?id=wip:faction:section6:commission:iss-hope
It looks like the way that string arrays are being initialized is not compatible with current PHP versions (my server is using 7.3) but I'm not an expert.