Regardless of contents of the "-profiles" parameter, C:\Program Files (x86)\Steam\SteamApps\common\Arma 3\MPMissions remains the only location for mission scenarios!
20:12:52 Can't find a mission with template name: 'NMD-SANDBOX-TANOA.Tanoa', skipping to next mission.
20:12:52 In last 1000 miliseconds was lost another 49 these messages.
Also, the "https://community.bistudio.com/wiki/Arma_3_Dedicated_Server" page further specifies the "-profiles" parameter as redesignating the MPMissions folder! ie:
"d:\Games\Arma3\A3Master\ MPMissions\ This is where custom made mission.pbo's need to be placed)"
The log file should also explicitly state the location the arma3server was looking for the Mission Scenario or PBO file. Such an omission likely caused my 2-3 hour problem here.