LE 8.02 on Wetek Core: AC3 Transcode 2 SPDIF, Audio Drop-out

Hi not sure if my issue resides with my hardware (Wetek Core), OS (LE 8.02) or Kodi 17 itself (my first time using all 3). Hoping somebody here might be able to enlighten me.

Only available 5.1 input to my receiver is via SPDIF. Works great with AC3 pass-through but I have issues playing AAC 5.1 using Kodi's transcode to Dolby Digital option. Often plays okay for a little while (sometimes minutes, more often only seconds) until the audio starts cutting out or drops to an inaudible volume on some channels.

Has anybody experienced similar or know what might be causing my issue?

Thanks.