It is convoluted why this is happening, but what is going on is _Meta is prefix is something that is added for legacy purposes. There is a flag that is being set in the config.idb file that indicates a Legacy Mode if one of the built in programs is loaded and nothing is changed before the initial save. This legacy mode ensures that users who are replacing simulators they created in 7.x with the new programmable simulator will not have to recreate their tags.
So what has happened is you started with one of the built in simulators and it got saved in its default state. Then it got modified, which persists the legacy flag, and exported. The export does not contain information on if the legacy flag was set.
When the export was again imported via the CSV option, the Legacy flag isn’t set and you are now in the situation where your OPC tags don’t have the correct opcItemPath.
There are two options to fix this:
Recreate the OPC tags
In your import file, manually add _Meta: before the value set in the Browse Path column and re-import the program.