Seemingly minor revision under review for two weeks. Is this common? This is a follow-up question on "Why call it a &quot;major&quot; revision if the suggested changes are seemingly minor?" 

I have submitted the revision two weeks ago and it's still showing as "under review." The paper has been under review for 1 year and 9 months. In general, if such scenario happens when should one expect a decision?
2 weeks of review time is really not very long, even for a minor revision (which, strictly speaking, yours apparently isn't, at least not to the editor). There is no way for us to know how long it will still take, but the unfortunate truth is that I see little reason to believe it's gonna be much faster than any previous (major) revision.

In reality, reviewing time often depends little on the actual amount of change. Instead, reviewers often get allotted a fixed amount of time (e.g. 4 to 6 weeks in computer science), and will get around to actually doing the review when this time is almost over. That your paper has been under review for long already is not something that reviewers will be aware of, or care very much about.