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Copying and repasting instances will tack on an incrementing (number) I'm not sure if this is a feature or a bug, the way it worked in TVP11 was just fine and allowed us to use the update instance script, right now if i try to modify copy and pasted instances it will not work.

In addition, at the very end of this video, making changes to a pasted instance and undoing will make this strange behavior of tacking on multiple incrementing (numbers)

I experienced same.

When I copy the instance and paste it, I hope instance name is just same as original one.

Just simple copy&paste is making timeline so unrecognizable.

and it makes difficult to using like 'Apply Current Content On Instances With Same Name'
using Scripts using the Instance name.
It requires more action to user than previous, to use as previous.

Thank you for your contribution. The team was able to reproduce the issue and solve it. The fix will be available in a future update.