XF 2.2 ErrorException: Template error: [E_WARNING] Attempt to read property "____" on null

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I have a quite old custom addon that suddenly started to throw this error on occasion. The dev is unfortunately out of contact. I did very recently update xenforo from 2.8 to 2.13 as well as my php version to 8.2, but that was a few weeks ago and this error started occurring the last few days. Finances are a little tight at the moment so before I sink money to this I was wondering if this is maybe a known issue and what approach I could take to resolve it?

 

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I actually just realized the same day the errors started was when I updated Social Groups by @truonglv so I will post this error to him first, just wasn't expecting it to break another one.