Grindstone effect not applied when used simultaneously with Fighting Fungus, cooldown still starts

Description

Short description of the issue:
When Fighting Fungus and Grindstone are activated at the same moment (pressing both artifact keys simultaneously), the Grindstone's damage buff is not applied at all. However, the Grindstone's artifact slot still goes on cooldown as if it had been used successfully. Activating them with a short delay between them works correctly.

Steps to reproduce the issue:

1. Equip Fighting Fungus (slot 1) and Grindstone (slot 3).

2. Enter any mission.

3. Press the Fighting Fungus key and the Grindstone key at the same time.

4. Attack enemies and observe the damage and the active effects.

Expected result:
Both effects are applied: increased attack speed from Fighting Fungus and extra damage from Grindstone.

Actual result:
Only the Fighting Fungus effect is applied. The Grindstone buff is not active (no extra damage, no effect indicator), but the Grindstone slot still goes on its full cooldown (4 s), so the artifact use is wasted.

If the Grindstone is activated first and Fighting Fungus a moment later, both effects are applied correctly. This suggests the issue only occurs when both artifacts are triggered at the same time.

Attachments
Video showing two fights:

1. First fight: Grindstone and Fighting Fungus pressed simultaneously. Only the Fungus effect is applied, and the Grindstone goes on cooldown without any effect.

2. Second fight: Grindstone pressed first, then Fighting Fungus with a short delay. Both effects are applied correctly.

Also attached: screenshots of both artifacts.