Print Designer Report Layout Corrupted

I created a sales invoice based on the Sales Invoice PD v2. After an adjustment of the footer, the footer itself shows on top and bottom of the page but my whole body is gone. Just gone, a day of work.

Is that a known issue and is there a way to restore my work?

Frappe Framework: v15.100.0 (version-15)

ERPNext: v15.97.0 (version-15)

Print Designer: v1.6.5 (develop)

I have flagged my own topic as spam in error because of the response above (flagged then as well). But I am still hoping for valid answers. Thanks

Unfortunately it has occured again today while I was editing the print designs footer.
The footer then gets mirrored to the top of the page overlaying the header and the body disappears. This must be a (serious?) bug.