Your mites. We ALL gt them time to time
However you do want to try to eradicate them if at all possible.
Yes, basically harmless...but this can get out of hand.
I just wanted to add that IF they get into the red eye tree frog enclosure they will stress-out your frogs.

Mites are free! The hitch a ride with the crickets. Crickets are disgusting !
They are more work than the frogs
Keep the cricket bin spotless ( remove the cricks ) and run it under HOT tap water/ wipe down the entire bin ( in and out) including the lid.

If they are very visible ---the you likely have a lot

Wipe down the entire area where any insects bins and containers are kept with an old wash cloth drench in rubbing alcohol ( supermarket) and then rinse.
Obviously, you don't want this cloth to touch anything the frogs will come into contact with.
I would move the cricket bin to an entirely different area for now.
The rubbing alcohol is a great product to use on more of a regular basis to keep your work area clean.

I have this ....but have not used it.
I purchased it to simply be prepared as I typically keep 25 or so fruit fly cultures at one time.
Mites in the ff cultures are not good
Josh's Frogs Bug Blade Mite Control Powder (5 oz) | Josh's Frogs
If I get mites in my cricket bin ---OUT it goes ---> cricks and all !
As Paul mentioned, it's good idea to purchase a smaller amt of cricks more frequently/ and clean the bin between new batches. That way ....they will never smell ! If the cricket bin smells ---> it is not being cleaned often enough.
So, size of the batch and bins can make a huge difference.

Do you see any walking inside the red eye enclosure?
If so, may I respectfully suggest you wipe down the interior glass of the red eye enclosure with a soft cloth drenched in distilled water.
You may have to repeat this a few times.

***********************************

FYI there is a type of herp mite - that is a problem- called Trombiculids that can cause little bites ( areas of redness) on the frog's skin.
The frog is treated w/ ( I believe ) a very diluted tetracycline bath.
It's unlikely you have this if they were found in the cricket bin.