Last few days I’ve been getting weird behaviour on editing criteria on unsaved searches, or trying to save a previously unsaved search. Time outs, not remembering the criteria etc. just me?

saved search has timeout in edit mode and in a view mode also, it's a standard behavior. As for the csv import you have to save you import and then use it. If you start a new one then it just shows the first element which is Accounts.

I know there is a time out, but this is happening seconds after the first run. Not sure what you mean about CSV - I am specifying Transaction > Sales Order but the mapping page shows the option for Accounts. In both cases these are things I have been doing for years which are now not working. I’ll clear all my caches and try again.

Clear cache. Different browser. By the time you document it, it's usually fixed. I know there is a weird intermittent problem that a saved search I've saved and working on will give a particular error on save and then it's gone. Missing form the list, internal id no longer used. Unable to be reliable replicated. Sometimes I wish I had a black box type screen record of what happened.