Knud
It is an understandable failing in us all that we cannot resist the bargain bulbs
Frit raddeana is a very early rooting species often it is making new roots before the old foliage dies away so I have a suspicion that your bulbs roots may have initiated and been killed off.
If this is the case then the bulbs will go into what I call survival mode and there are two possibilities.
1) They will put up some leaves and possibly try and flower purely from the energy stored in the bulbs and what can be absorbed directly through the bulb without the roots. Foliar feeding in growth is beneficial in this case.
2) They may not appear above ground at all this year but a new bulb will still form as the old one passes on its store. Unlike true bulbs Fritillaria bulbs die every year as a new one is formed.
It is just possible, depending on how the bulbs were stored that the roots remained dormant and they will grow in which case it is my experience for late planted bulbs to flower very early.
Good luck and keep us infomed of their fate.