GPU Acceleration (processing) first worked, now its grayed out!?

Im using the latest Version mac OS 10.14.6 and the Graphic processor for image worked fine in Lightroom 8.4 for about 4 weeks. After the 8.4.1. Update i cant use the "Graphic processor for image" (option is grayed out). A downgrade back to v8.4 didnt help here. MacOS version wasnt updated in meantime (its still the latest). Is this a Bug?

Lightroom Classic-Version: 8.4.1 [ 201909111355-eb9b68f0 ]
Lizenz: Creative Cloud
Spracheinstellung: de-DE
Betriebssystem: Mac OS 10
Version: 10.14.6 [18G95]
Anwendungsarchitektur: x64
Anzahl logischer Prozessoren: 8
Prozessorgeschwindigkeit: 4,0 GHz
Integrierter Speicher: 32.768,0 MB
Für Lightroom verfügbarer phys. Speicher: 32.768,0 MB
Von Lightroom verwendeter phys. Speicher: 1.884,4 MB (5,7%)
Von Lightroom verwendeter virtueller Speicher: 6.296,0 MB
Cache-Speichergröße: 109,3MB
Interne Camera Raw-Version: 11.4.1 [ 291 ]
Maximale Anzahl Threads, die Camera Raw verwendet: 5
Camera Raw SIMD-Optimierung: SSE2,AVX,AVX2
Virtueller Speicher in Camera Raw: 288MB / 16383MB (1%)
Physischer Speicher in Camera Raw: 289MB / 32768MB (0%)
Monitore/Anzeigegeräte: 1) 5120x2880

Informationen zum Grafikprozessor: 
Metal: AMD Radeon R9 M295X



Anwendungsordner: /Applications/Adobe Lightroom Classic
Bibliothekspfad: /Users/osman/Pictures/Lightroom/Lightroom.lrcat
Einstellungen-Ordner: /Users/osman/Library/Application Support/Adobe/Lightroom

Installierte Zusatzmodule: 
1) AdobeStock
2) Aperture/iPhoto-Import-Zusatzmodul
3) Facebook
4) Flickr
5) HDR Efex Pro 2
6) Nikon Tether-Zusatzmodul

Config.lua-Flags: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: Ausgang (integriert)
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 44100
Build: 12.1x4
CoreImage: true
GL_ACCUM_ALPHA_BITS: 0
GL_ACCUM_BLUE_BITS: 0
GL_ACCUM_GREEN_BITS: 0
GL_ACCUM_RED_BITS: 0
GL_ALPHA_BITS: 8
GL_BLUE_BITS: 8
GL_DEPTH_BITS: 24
GL_GREEN_BITS: 8
GL_MAX_3D_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_UNITS: 8
GL_MAX_VIEWPORT_DIMS: 16384,16384
GL_RED_BITS: 8
GL_RENDERER: AMD Radeon R9 M295X OpenGL Engine
GL_SHADING_LANGUAGE_VERSION: 1.20
GL_STENCIL_BITS: 8
GL_VENDOR: ATI Technologies Inc.
GL_VERSION: 2.1 ATI-2.11.20
OGLEnabled: true
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