Blank entries in PM Inbox

Today, another geek sent a private message to me. I received an email from vBulletin with the content of the PM and sender's geek name, as usual. I accessed FPGeeks, went to my Inbox, and there is only a blank line with the sender's name, and no title of the message. Furthermore, the message is not there.*

So...I used what I knew from the email and using vBulletin, I drafted and sent a reply message to the other geek, and a blank line for the message I sent appears in MY Inbox with only my name (as though I sent it to myself), no title and no message. But the message and title also appears in full in my Sent box.

Is this the beginning of a software mudslide?

*Edited to add: the missing message appears in Tapatalk!

The PM system is not standard for the Forum software. It was an add-on installed later. It never seemed to mesh well and it gets really weird when tapatalk gets involved or you try to delete your messages.