So last January, I posted here about dllhost.exe randomly opening and closing in the background with my username, legit process and legit process ID. I was assured that this was nothing to worry about, and it eventually went away.
About a week ago, it showed back up. Same behavior, randomly opening, staying open for about 5-10 seconds, then closing. Frequency of anywhere from hours between to one right after another. Legit process (it's come mostly from System32, though I've seen it pop up a few times from SysWOW64, both legit), legit ID (F9717507-6651-4EDB-BFF7-AE615179BCCF), running from ComSysApp. I've run ESET and MBAM, both came back clean. I even ran JRT and TDSSKiller to see if they would do anything, they came back clean too. Still comes up after all of them. Less than 3 MB each time. Nothing seems to be misbehaving there, though I still have no idea what it's doing each time.
All this is the same as the last time, except for one thing that happened a few days after it started again: the dllhost.exe process run by SYSTEM is no longer running. No error messages or anything to explain what happened. Quite literally there one day and gone the next. Everything seems to be running fine without it, though. Not even the barest hint of an error message or anything going wrong.
Should I be concerned, or is this just my computer being weird?