No crank, no start - loose starter and alternator connections ?

[Forjox]

My wife’s 2015 2.0L Edge Titanium wouldn’t start yesterday. It’s got 105,000 miles and this is the first time this happened. I went to rescue her and started checking all connections as it clicked loudly like the starter was engaging but not turning. Loosened and tightened the ground at the strut pillar, checked battery connections, then tried to jump start. When it clicked I noticed a spark down at the starter connection. Upon inspection, I found the cable connection at the solenoid loose as I could wiggle the wire, but the nut seemed tight. After securing enough tools, I tried tightening the nut to no avail until I loosened it first then tightened it home. (About 1 turn) I surmise that this has been loose since new and some corrosion set in at the threads that I had to overcome the extra friction by loosening before tightening. I’m surprised I didn’t find others online with the same issue even though I found a recall related to loose starter and alternator connections for the 2018 models. Anybody seen this issue before?