Cannot edit coin, it deletes the text I entered as source and states I have to enter a source

Germany 1 Mark
https://en.numista.com/catalogue/contributions/modifier.php?id=846
enter anything as source, click the button
->
"Error
Please specify the sources of the information."

and the source box will be empty again

This does not happen with other coins

Could the problem be the size of the coin sheet?
When it shows the error, the variant list is only loaded up to 1994 A
and that is the point where some comments are missing (1994 D and F) - could they have been deleted by this bug at some time?

(edit in 2020: the problem was solved at some point from when on the sheet was loaded completely)

Hello,
Do you still experience the issue? If yes, which browser are you using?