The bonuses to base damage that barbarians get with or without a weapon disappear without notice upon resting.
Here’s an example:
• Leather Whip Properties
None.
• What my character sheet shows:
Damage: 1-2 + 11
+2 Slashing Damage
After resting
Damage: 1-2 + 11
This corresponds to the actual damage range.
Explanation: Barbarians get too comfortable.
The damage bonus can be reapplied by reequipping a weapon, but I would hope for a permanent fix eventually.