I've seen this too. For now, the workaround is that if you select "Edit Watermark," when you're finished editing be sure to re-select the same watermark. If you don't, the watermark pop-up menu will be blank.
It appears to be a known bug that only happens in the current version. Hopefully it can be fixed in the next update. There is a page for it at the Photoshop/Lightroom Feedback site. I have added my vote to the page:
Thanks SaturnV Thats it and it's exactly what I've had to do to get around it... It's so annoying and also time consuming when you have over 250 shots to edit :-(
Thanks for getting back to me, really appreciate it :-)
At time of editing the watermark, please save it as preset and give it a name, once then apply that watermark preset on your image and then export.
Yep done that Mohit... Thanks, But I still need to keep selecting it and yet before? I never had to.