I cannot help but notice that, in some early Latin borrowings into Croatian, 'sk' remained 'sk' (as in the toponym Skradin, from the ancient name Scardona), and yet, in other early Latin borrowings, such as "baškotin" from "biscoctus", 'sk' changed to 'šk'? Why is that?
"Baškotin" was obviously borrowed before change of short 'i' to schwa, which occurred way before the Havlik's Law (soon after the Havlik's Law the schwas turned to 'a'), so I think it can safely be dated to at least as early as around 10th century (already in the Baška Tablet, the earliest written text in Croatian, the front yer and back yer were used interchangeably, suggesting they were both schwas at the time). Furthermore, the suffix -in (usually from Illyrian -ona, though I don't know how likely that is for the word "baškotin", that it is borrowed from Illyrian) is also a sign of very early borrowings, later borrowings tending to have -un (such as Solun from Salonike), right? So explaining the difference between the outcome of 'sk' in Skradin and "baškotin" using the timeline of the Croatian historical phonology (by claiming "baškotin" was borrowed significantly later than Skradin) does not make a lot of sense, does it?