Some Wmarts have phased out their PNY microSD/SD cards and replaced them with cheap onn brand microSD/SD cards.
You will think they are a bargain ($5 for a 16GB card) until you try to eject them from your sonar unit.
They are just a fraction of a mm shorter than most microSD cards.
They work just fine, but I've needed a safety pin to wiggle them out of two different units.

I'll reserve them as back up to the back ups for waypoints etc. ; but I will avoid putting them back in the units at all costs.

I have had no problems with the sandisk and PNY brand cards.

My navionics card does the same thing, I have to use tweezers or a knife to remove it.

Of interest, what type of fish finder do you have? Mine are an Elite 5 HDI and an Elite 7 Chirp.
Yes, the fish finder manufacturers certainly make the microSD card slot deep with a thick lip around the circumference. I'm sure this is for water resistance.
It leaves very little tolerance for microSD card size.

I haven't had any problems with the PNY brand and Sandisk.

Found some PNY at a different Wmart this morning.

I have gen 2 12’s, same problem in both graphs with the card. My regular SD cards work fine, but they are older Sony & PNY cards

Thanks; good to know.