I am absolutely sure. It just happened againg. That means that it was not the eQSL upload. I mentioned eQSL for full disclosure but as I now know, it is not the problem.
I have the debug log for day for this instance and I will now turn on the debug log for JTAlerts. Like I said before, this is randome so there's no predicting when it will happen again.
I was sending some text messages during the use this time. If the QSO partner is online, I often send a "Tnx QSO. 73. Carl" message. Sometimes that leads to a few exchanges which are like an extended QSOs and can be very interesting.
I'll keep an eye on it to see if the messages interfere.
Carl - WC4H