Well that sucks, maybe, hopefully they can be saved with the liberal addition of some sauce.
Yep, too heavy a smoke can taste bitter, e.g. rolling thick white smoke versus the sought after thin blue smoke.
And as Mr. Neeley says stale trapped smoke can too, check your vents, did one or more get bumped closed or partially closed?
Also it may be time to give your smoker a cleaning? Burning grease/oils and creosote can impart a bitter taste.
Creosote can even make you tongue feel a bit numbed.
Give it a good cleaning and make sure you've good airflow.