The skill point book did not dropped

Description:
Killed Blind Beast in Isle of Kin in solo play on an instance with “+” / empowered modifier. The boss was killed successfully, but the Book of Passives (+2) did not drop.

Expected Result:
Blind Beast should drop a physical Book of Passives granting +2 passive points.

Actual Result:
No book dropped.
Loot filter was enabled but does not hide any items.
Item labels were checked with ALT.
Inventory was not full.
This was the first completion of this boss on this character.

Im_Just_Farting
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