As reported here there is high battery drain while suspended (out of the box PureOS setup). Affected models seem to include 13v2, 15v2, 15v3. Bios include Coreboot 4.7-Purism-4 and AMI. OS include PureOS, Debian, Ubuntu.
I am also experiencing the drain issue. However, I am running Ubuntu 18.04 and seeing:
[ 1.564862] [drm] Finished loading DMC firmware i915/skl_dmc_ver1_26.bin (v1.26)
So I don't think the error above is related. I ordered Samsung memory and will see if it makes a difference.
My new RAM is CT16G4SFD824A C16FE
My old RAM was CT16G4SFD8213 C16FH1
An overnight suspend of ~8h resulted in 86%–>79%, or ~7% battery charge loss, a marked improvement from the ~60% I was seeing.