I tried to move 2 distinct pages on nlwiki to a location with an existing redirect, which results in a confirmation page where I can check that the target page should be deleted. In both cases, confirming would then lead to a fatal error.

The pages were:

• https://nl.wikipedia.org/wiki/1-Aminocyclopropaan-1-carbonzuur to https://nl.wikipedia.org/wiki/1-aminocyclopropaan-1-carbonzuur
• https://nl.wikipedia.org/wiki/Jeanne-Louise_Calment to https://nl.wikipedia.org/wiki/Jeanne_Calment

Workaround was possible (in the first case) by manually deleting the destination page, and then renaming regularly.

For the second rename, the error message was: "[XDpVIApAIC8AAIb@TJ4AAAAM] 2019-01-12 20:59:12: Fatal exception of type MWException"

I kept the latter move intact (I didn't use the workaround) so that it can be reproduced by others.