Please can you urgently check this bug in the "Any TM" module.
Hello there Paul. It is good that Nicola was careful to mention that she was using the Any TM plugin. I had the same issue, but in Trados 2014, and it also occurred in Trados 2017. What was happening is that the setting "Overwrite" or in the later versions "Merge" was not working, instead the TM was behaving as if it was set to "Add New", all the time, which makes the whole TM effectively useless. We are simply referring to the standard options for the way the target segments are written to the TM when you confirm them. If you edit them and then confirm them again, you don't want each unedited version to be added to the TM! I found these options under "Batch Processing", in the Project Settings and Options, which is a bit strange, because this is a basic operation for working with a TM in Trados, not just when you do a batch update of the TM.