See ForestryMC/ForestryMC#1542 for a similar instance of this.

InventoryTile constructs a SidedInvWrapper when requesting an IItemHandler instance. However, when the facing argument is null, a SidedInvWrapper is still constructed, which can cause issues when trying to use it - instead an InvWraper should be returned.

https://github.com/bdew/bdlib/blob/c37db5723a8b2ec324a8fefc4781ae0f1def23b5/src/net/bdew/lib/tile/inventory/BaseInventory.scala#L80

The mod has been recently updated to MC 1.16, older versions are no longer supported.
I'm mass closing older issues to clear up clutter in the bug tracker.

If you find this issue still exists in the current version feel free to reopen it.