Hi Gavin, this is a know issue in all versions since the first update after Chromium interaction was implemented into BP.
Supposedly it got solved in 7.0, but I cannot tell, as we are still using 6.4.
Basically, BP uses a certain port for connecting with Chrome, but it does not close it after interacting with it. The connection remains open and the next time BP tries to connect with Chrome, the port appears locked so (I guess) it attempts a new connection and there the elements are not available, as the previous connection, which was not closed, is still using them.
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Ramón Requena López
RPA Developer
Magenta Telekom
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