When setting Parallel Labs to research several levels of an infinite tech (e.g. Health 1 to 7), the Parallel Lab will continue to research Health level 1, while the player gets increasing tech levels every time the Parallel Labs complete Health level 1 again.
Adding a level of a different tech (e.g. Mining Productivity level 3) to the queue causes the Parallel Labs to move on to research Health level 2 etc. Removing this tech from the queue, even if not completed, then causes the Parallel Lab research queue to reset back to Health level 1, even if the player is at health level 20+.
When trying to reproduce this with Mining Productivity level 3 in the Parallel Lab, the issue did not seem to happen - the research completion of Mining Productivity 3 in the Parallel Lab did not cause the player's Mining Productivity to increase from 41 to 42.
After completing Mining Productivity level 3 in the Parallel Lab, the issue stopped being repeatable - Health research levels for the non-player force were remembered, and stopped adding levels to the player force research which was much higher.