I had similar experience last week, Nello
I put in bid at ASK, they fill 12% at .013, then keep ask there but I don't get filled, a few minutes later Iput in ASK at .0135, no fill... they skip over me, and then raise ASK to .0135, and they continue to skip my order
they go to .014 ASK, so this time I don't bid at .014, I bid at .0145, and they dont fill me at all, they raise the ask to .0145, continue to skip me... and they appear to be filling orders fill orders at .0145 and below but not me
then I raise to .015 and they go to .015, but I don't get filled
they raise it to .0155 and I gave up chasing it