According to their product data sheet, this product does require scarification before applying another coat after 12 hours of curing @ 70 degrees.
6) RECOAT OR TOPCOATING: If you opt to recoat or topcoat this product, you must first be sure that the coating has tacked off before recoating.
However, all previous coats should be deglossed to insure a trouble free bond prior to application of recoats or topcoats. Colder temperatures will require more cure time for the product before recoating or topcoating can commence. Before recoating or topcoating, check for epoxy blushes (a whitish, greasy film or deglossing). If a blush is present, it can be removed by any standard detergent cleaner prior to topcoating or recoating. Many epoxy coatings and urethanes as well as multiple coats of this product are compatible for use as a topcoat.
This is not uncommon with 100% solids epoxies. They cure extremely hard and require scarification or "deglossing" before another coat is applied if outside the re-coat window. Since your prime coat has been curing for a few days, I would most definitely give it a light sanding and a solvent wipe (denatured alcohol) before applying your 2nd coat.
Something like this works pretty well with some 80-100 grit sandpaper if you cannot mechanically abrade.
I've attached the product data sheet.