Thanks for this confirmation @ChuckPa
I am currently using a Dockerized PMS (latest 1.14.0.5465 version available), but I can try a regular Synology package beta version if you have one.
Thanks 
PS : probably not related, but there is also another issue with PMS on these J3355/J3455 CPU series NAS (Apollo Lake generation), with color corruption during downscaled transcodes as reported here : Color corruption on resize when HW Transcoding HEVC content to h264, + 4K subs - Synology DS918+ NAS - #18 by Ridley
There is a workaround found in that post waiting for a fix from Intel, but there is no sign for an imminent fix at all 
Could that workaround be directly implemented into PMS builds in the meantime ?
