System.InvalidOperationException: 'ReadSubtree() can be called only if the reader is on an element node.'

From time to time, I encounter a strange exception when running the RunAnalysis method of the FemDesignConnection class.
As far as I can remember, it only occurs when multiple calculations are executed concurrently. In my code, the RunAnalysis method is wrapped in a lock statement to ensure that only one thread can access it at a time.

Do you have any idea what might be causing this?

Ehi Igor.
Are you able to reproduce the bug consistently?

Running multiple analisys in parallel might cause issue currently.

However, the issue seems related to reading result maybe?