I've been retired for a while but I keep doing collect tasks for tranining.
Today I logged in as I do a 1-2 times per week, activated a premium card and went to bersund NPC with enought valk braids to finish my task. Osvald took my itens but instead of offering me a new task, he asked if I wanted to complete or cancel, at first I was confused, tought i miss read something, so I went to buy a few more braids, tried again, and ended up with the same dialogue. Resuming he took twice my itens but didnt let me complete the task, resulting in the loss of 110 valk braids and a premium card ;o

[12:33:45] Osvald: How do you wish to be rewarded? It is possible to choose experience, gold, or if you want, some training.
[12:33:53] Saudoso Bigode: training
[12:33:53] Osvald: Incredible, you did it! Let us begin the training...
[12:34:10] Saudoso Bigode: task
[12:34:10] Osvald: Your current task is to collect 55 valkyrie braids. Have you completed your task or do you want to cancel?
[12:34:18] Saudoso Bigode: complete
[12:34:18] Osvald: How do you wish to be rewarded? It is possible to choose experience, gold, or if you want, some training.
[12:34:20] Saudoso Bigode: training
[12:34:20] Osvald: You are not done yet! You are supposed to bring me 55 valkyrie braids, which you do not carry with you!
[12:35:37] Saudoso Bigode: hi
[12:35:37] Gertrude: Hey, Saudoso Bigode!
[12:35:39] Saudoso Bigode: trade
[12:35:39] Gertrude: Let me know if you found something.
[12:35:54] Kilter is about to expire in 15 seconds.
[12:36:04] Saudoso Bigode: trade
[12:36:06] Saudoso Bigode: hi
[12:36:06] Gertrude: Hey, Saudoso Bigode!
[12:36:07] Saudoso Bigode: trade
[12:36:07] Gertrude: Let me know if you found something.
[12:36:22] You bought 36x a valkyrie braid for 252000 gold via the market.
[12:36:31] The offer has been removed from the market.
[12:36:45] Your offer was added successfully.
[12:40:26] Saudoso Bigode: hi
[12:40:26] Osvald: Hello, Saudoso Bigode! Having trouble? The guards can help! Or perhaps, are you up for a challenge?
[12:40:29] Saudoso Bigode: task
[12:40:29] Osvald: Your current task is to collect 55 valkyrie braids. Have you completed your task or do you want to cancel?
[12:40:31] Saudoso Bigode: complete
[12:40:31] Osvald: How do you wish to be rewarded? It is possible to choose experience, gold, or if you want, some training.
[12:40:32] Saudoso Bigode: training
[12:40:32] Osvald: Incredible, you did it! Let us begin the training...
[12:40:37] Saudoso Bigode: task
[12:40:37] Osvald: Your current task is to collect 55 valkyrie braids. Have you completed your task or do you want to cancel?

yes it is still bugged , gm no fix it yet.

I had the same problem right now, delivered 45 lion tails and got no reward for it! and the asked me again for the same thing!!
@GM Quillon