I'm also on PIA, but I'm using Wireguard and getting a similar error loop:
2023-02-27 14:31:51,587 DEBG 'start-script' stderr output:
parse error: Invalid numeric literal at line 1, column 10
2023-02-27 14:31:51,588 DEBG 'start-script' stdout output:
[warn] Unable to successfully download PIA json to generate token for wireguard from URL 'https://www.privateinternetaccess.com/gtoken/generateToken'
[info] 12 retries left
[info] Retrying in 10 secs...
EDIT: Attached my log
supervisord.log