That was a bug we had with the rendering of the confirmation corner icons. It is fixed in 2016 SP05.
Thanks! Bad news for me though. Our corporate IT now "packages" the installers, so I will probably not see this upgrade for years. It took over a year for them to roll out this SP4 installer. Before that we were on SW 2014.
If you have subcription when the SW2016 SP5 release then you can upgrade to sp5 easily since it does not have a high impact like when upgrading to new version of SW. just remember to back up the user setting using copy wizard