AFAIK Wasps have always been extremely supportive of players gaining international caps.
Totally agree, Wasps have never stood in the way of anyone representing their country. However, it's one thing when you have an academy youngster going on to achieve international recognition (eg Willis, Launch), or you bring in an established or emerging international (eg Robson, Crossdale) in the full knowledge that you may be without them during international windows at some point; quite another when you invest in a player believing they have no realistic prospect of playing international rugby again (eg Fekitoa, JTA, Fifita) and the lose them for a chunk of the season unexpectedly. Recruitment will have been done with this in mind to ensure that clubs retain a strong squad through international periods, and this will certainly have been a consideration in salary discussions too. Clubs will have to change their approach, and who knows if some might insert a contract clause in order to guard against being caught out in such a way.
As an example, Bristol signed Hughes as a current England international, expecting to be without him at times and he's not been in an England squad since, so they will have been happy with that outcome and that probably earnt him a few extra £££ on his next contract. Now he's about to become eligible for Fiji.