# \[Bug\] Engine OS 5.1.1 – Acapella and Instrumental STEM FX buttons stop working when "Hide Title/Artist" is enabled on PRIME 4 G2

**URL:** <https://community.enginedj.com/t/bug-engine-os-5-1-1-acapella-and-instrumental-stem-fx-buttons-stop-working-when-hide-title-artist-is-enabled-on-prime-4-g2/71377>\
**Category:** Standalone Controllers\
**Created:** [October 23, 2026, 6:47am UTC](https://community.enginedj.com/t/bug-engine-os-5-1-1-acapella-and-instrumental-stem-fx-buttons-stop-working-when-hide-title-artist-is-enabled-on-prime-4-g2/71377 "2026-10-23T06:47:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![bazookon](https://community.enginedj.com/letter_avatar_proxy/v4/letter/b/49beb7/32.png) [@bazookon](https://community.enginedj.com/u/bazookon)\
**Post date:** [October 23, 2026, 6:47am UTC](https://community.enginedj.com/t/bug-engine-os-5-1-1-acapella-and-instrumental-stem-fx-buttons-stop-working-when-hide-title-artist-is-enabled-on-prime-4-g2/71377/1 "2026-10-23T06:47:02Z")

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**Device:** Denon DJ PRIME 4 G2 **Firmware:** Engine OS 5.1.1 **Issue Type:** Bug / STEM FX

**Bug Description:**

I discovered a bug in Engine OS 5.1.1 on my Denon DJ PRIME 4 G2.

When the **“Hide Title/Artist”** option is enabled under Settings → Device, the physical **ACAPELLA** and **INSTRUMENTAL** STEM FX buttons stop working.

Disabling “Hide Title/Artist” restores their normal functionality.

**Steps to Reproduce:**

1. Open Settings → Device.

2. Enable “Hide Title/Artist”.

3. Load a track and try using the physical ACAPELLA or INSTRUMENTAL buttons.

4. Notice that the buttons no longer function as expected.

5. Disable “Hide Title/Artist”.

6. The buttons work normally again.

**Expected Behavior:**

The ACAPELLA and INSTRUMENTAL STEM FX buttons should function normally regardless of whether “Hide Title/Artist” is enabled.

**Actual Behavior:**

Enabling “Hide Title/Artist” causes both physical STEM FX buttons to stop functioning.

**Workaround:**

Disable “Hide Title/Artist” in Settings → Device.

**Additional Information:**

This appears to be an unintended interaction between a display/privacy setting and the hardware STEM FX controls. These features should operate independently.

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**Author:** ![aaaguy](https://community.enginedj.com/letter_avatar_proxy/v4/letter/a/c5a1d2/32.png) [@aaaguy](https://community.enginedj.com/u/aaaguy)\
**Post date:** [October 23, 2026, 8:09am UTC](https://community.enginedj.com/t/bug-engine-os-5-1-1-acapella-and-instrumental-stem-fx-buttons-stop-working-when-hide-title-artist-is-enabled-on-prime-4-g2/71377/3 "2026-10-23T08:09:22Z")

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Thanks @bazookon - We will take a look!