I do not have your symptoms… my instance is running fine (knock on wood! 
)
actually got curious and looked at my log, found in the log an error quite similar to yours that appears “regularly” for a few hours and does not appear for hourS…
it is like a cycle so I suspect it is related to the application pool recycling.
Apparently it is related to wincache and dig to find this:
https://suitecrm.com/suitecrm/forum/installation-upgrade-help/1007-windows-and-iis-permissions-issues-suggested-fix-for-anyone-using-this-platform?start=30
look at the end he toyed with some settings…
“wincache.ucachesize default 8 increased to 85 (max) [color=#ff0000]no fastcgi error since Nov 8 2017[/color]”
Mine is set to 16
if I compare my settings to what he indicates, apprently I tweaked it at some time…
wincache.apppoolid no value no value
wincache.chkinterval 30 30
wincache.debuglevel 0 0
wincache.enablecli On On
wincache.fcachesize 24 24 standard
wincache.fcenabled On On
wincache.fcenabledfilter no value no value
wincache.fcndetect On On
wincache.filecount 4096 4096 standard but looking to increase
wincache.filemapdir no value no value
wincache.ignorelist no value no value
wincache.localheap 0 0
wincache.maxfilesize 1024 1024 tweaked
wincache.namesalt no value no value
wincache.reroute_enabled Off Off
wincache.scachesize 64 64 tweaked
wincache.ttlmax 1200 1200
wincache.ucachesize 16 16 tweaked but looking to increase this weekend
wincache.ucenabled On On
xml