While testing the module it appears the URL alias for the existing node gets either deleted or changed to point to the new node.

Before translating we had an alias testing-pathauto which was set to node/118 and was set to English language.

After translating we (correctly) had an alias testing-pathauto pointing to node/119 and set to German language (yes the title was left unchanged and so the new node has the same alias).

However, the original alias (to node/118) no longer exists and there is a duplicate of the alias going to node/119 and is also set to German.

I've had a brief look at the code but without knowing what the translation management module does, it's hard to know what's going wrong, if you need any further information, let me know.