No Interrail in Lithuania ?

On their website, Lithuanian railways mention Interrail and Eurail passes and that they give a 100% discount:

https://ltglink.lt/en/discounts-and-concessions

In my opinion, that implies a free but mandatory reservation, although they describe it in a strange way (in any case on the English page) and still say you have to buy them (which contradicts the 100% discount).

In the data they send to the European Timetable Centre, however, they don't seem to include mandatory reservations. That's why the rail planner app or the DB planner doesn't mention it. If reservation is indeed mandatory (although that would be quite strange for the local and regional trains), then their timetable data is incorrect or incomplete. @Nanja, maybe you could get clarification on which trains in Lithuania have mandatory reservations?

In any case, in 2019 I used the train from Kaunas to Białystok with an Interrail pass, without any reservation. I doubt that a reservation would have been possible in that train - one friend didn't have Interrail but a normal ticket instead and didn't get a reservation either.