Something frustrating you will see on OTCQX are bots, There are automated trading platforms "bots" on the OTCQX trading NUG. They like to dance. That is not to say you can't buy those shares at the ask for 13.5.
Where I find the bots is when you become the best bid or ask, other bids or offers near you and opposing you will react instantly. Typically the other bids may fall into line behind you, and the best ask might backaway from your bid, in an effort to get you to pay more.
Two can play that game. If the market is not overly active, you can wait 5 or 10 minutes,then back off on your own bid. Often the offer will instantly come toward you, but not meet you.
Do that a couple times, then pounce. It can be sport.