For a few days I have had a problem adding new users because “Resource Id nnnn” appears whenever I add a new user. Not sure if that error is from my child theme or some other plugin. This morning I installed WordFence and I started getting the same issue you are describing about mismatched passwords. When I deactivate WordFence, the mis-matched password problem goes away, but my strange “Resource Id nnnn” message is back. I recommend you try deactivating WordFence.