Steps to reproduce:

0. Install and configure mpd, set up polybar to use mpd plugin with <label-time> in format-online (as shown below), then run polybar main:

[bar/main]
font-0 = Noto Sans:pixelsize=11;1
# FontAwesome is needed to display "" symbol
font-1 = FontAwesome:pixelsize=11;1
modules-center = mpd

[module/mpd]
type = internal/mpd
format-online = %{F#6b6b6b}[<label-time>]%{F-}  <label-song>

1. Start playing music from mpd
2. Suspend your PC (for example, run systemctl suspend in terminal)
3. Wait for ~10 minutes, then turn on your PC

Expected behaviour:

mpd plugin shows normal elapsed time

Actual behaviour:

UPD. This happens not only after waking up, see #915 (comment)