Issue with epoxy floor staining

[Southbound]

Hi everyone, first post here. I was hoping I could ask a question. I had an epoxy floor put down in my garage about a year ago. I paid top dollar and was assured only the best material was used. I’ve been noticing for a while now brown stains appearing in various locations. I’ve attached a pic. They’re very rough, and almost like they’re etched into the surface. I’ve tried everything from Ammonia to acetone and nothing will take these up. I reached out to the contractor who installed it and he said I must’ve spilled something and now won’t return my calls. I’m absolutely positive these are not from anything I spilled. Any idea what these could be and how I may be able to remove them?
Thanks for the help!

 

[dirtydrew420]

Im no expert here by any means. But I did put a floor down in my own garage, and have a couple similar lesions. I'm pretty positive they're from contaminates and poor bonding with the concrete.(oil stains etc.)

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[dirtydrew420]

The only other way I produced stains like that on my floor was dropping hot bolts/nuts.

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[Garage Flooring]

I can't tell from the picture. Is there a clear coat over the epoxy? Is the stain in the clear or the color or both

 

[Southbound]

I appreciate the responses guys. There is actually 3 coats of clear coat. The stains are definitely on the surface. When rubbing your finger across the surface, the stained area is noticeably rougher than the surrounding unstained area. It’s almost like it’s etched into the surface. I haven’t tried sanding it at all so I don’t know if it goes down thru all 3 coats and then the color. If I didn’t know any better I would think something spilled on the floor and stained, since it looks and feels like a surface stain. But I know that’s not the case. They’re all small (anywhere from the size of a quarter to 2” or so) and scattered throughout the garage on one side. This area of my garage is an open area where nothing is stored and has no foot traffic

 

[Armorpoxy]

This may be from moisture in the slab migrating to the surface and trying to get out in spots and the moisture reacting with the concrete and causing efflorescence which is discoloring the coating. We have seen this before, not though a frequent occurrence.

Was any moisture or PH testing of the floor done prior to coating?