Message and thread content disappears from reply... sometimes

[canross]

This one has me stumped.
When replying to posts in a thread and some PM's, sometimes the replied to content won't show up quoted in my reply... but sometimes it will.

I've found two separate times this happens.

1) In threads if I choose "Reply with quote" the initial quick reply window shows the content I'm replying to surrounded by the [ QUOTE ] bbcode. However if I then click "Go Advanced".... the quoted text and any of my new writing disappears.

2) In private messages, some messages automatically insert the replied text surrounded by the [ QUOTE ] bbcode in the "Quick Reply" window as well as the "Go Advanced" window, while others never add the replied to text. It sortof seems like smaller PM's carry over their text more often than larger ones, but that's a guess more than any concrete fact. If I manually rebuild the replied text and bbcode it then carries over when you change to "Go Advanced etc".

The failed QUOTE issue also seems to happen when editing some posts, but I haven't been able to test it as much because of the 30 minute timer on editing.

I've tried this with Chrome, Firefox, Edge, and IE, and the success/failure is the same across each browser and the same for each PM and thread. Mostly it's a pain since I use quotes a lot in both PM's and thread replies so there's context for what I'm referring to, and one mistake and you lose all your text.