Tom,
I have had lots of liquid compasses develop bubbles, but I have never identified significant errors caused by them (and I have checked carefully). Any errors that might be produced are lost in the accuracy of the compass. If I need higher accuracy (still handheld), I use a Brunton Pocket Transit (in fact I use it most of the time if I know I am going to need compass because I am most familiar with it).
Respectfully,
Jerry