I know there's a limit as to how tall signatures can be, but I can't find the thread that explains it. I'm guessing that your two tickers, stacked vertically, exceed that limit. Is there a way to modify your signature code so they sit on the same line? (In the HTML generated by the board, there's a <br> tag between your two tickers, causing them to go on separate lines. I don't know what the equivalent looks like in the signature code.)
ETA: This isn't the thread I was thinking of, but it does have information and suggestions in it.
https://www.disboards.com/threads/please-read-new-signature-rules.1610271/#post-21298298