Sigma 30mm f/1.4 DC HSM "Art"?

I have been considering this lens, as I don't have the funds for the 31mm Limited and with Sigma's cashback it is down to £225 at some places.

However, I am wondering why so few retailers offer it in Pentax mount? For example my go-to shop for Pentax, SRS, only stock this lens in Canon and Nikon fit.

I know that there are some reported issues with AF for this lens. Are they so bad that retailers don't feel it is worthwhile selling it I wonder?

I had the same issue when I was trying to buy the Pentax mount version without success, but "luckily" I stretched myself to the 1.4, 35mm (ART) DG , which is FF compatible (DG) and as all the reviews I read, without exception concluded it is stunning even at 1.4.

So although I spent more than I wanted too the outcome was "lucky" in the sense that it forced me to buy this lens against my better financial judgment (and available budget) and it is without a doubt the sharpest independent lens I have used if not the sharpest standard length prime I have owned.

The problem that followed was I also tried the 1.4 DG 85mm version which is the same right across the aperture range: so now I am broke and happy with both DG primes.