I think apauto may have called me out because I wrote about this kind of struggle on one site several years ago. I tried all kinds of things over almost a year to get the situation to straighten out. The last thing I did before it seemed to get "fixed" was enrich the vocabulary on the intended ranking page with four natural "co-occurring" phrases that related to the intended ranking phrase.
Once I researched phrase co-occurrence for my intended keyword, I saw that my content had been written with too intense an SEO focus on one particular phrase - there were no other semantic signals present to say to Google "this page is ALL about [chartreuse software] - it doesn't just mention the phrase."
In fact it was quite a moment of insight and clarity. No one except for an SEO would write a page about [chartreuse software] the way I had. More normal people would have naturally included some wider semantic signals. I'd say I was having a 90s hangover.