Chat, after they put me through "you don't have a clue" nonsense Q&A ,agreed there's a problem and said they'd open a ticket, but I have no feedback, nor a ticket number.
Here's the deal:
Today, indoor cycle, wearing Fenix 6 Pro, with HRM-Pro (all firmware and updates current).
Activity registers 36 minutes moderate, 6 minutes vigorous, 36 + (6*2) = 48 minutes total. Cool, that tracks.
Look at Daily Summary GRAPH, started day at 119 intensity minutes for the week, after exercising I have 167 intensity minutes for the week. Brilliant! 167-119 = 48 minutes, very logical.
No other intensity minutes register on the GRAPH.
BUT, the summary above the graph on Connect.Garmin.com or the Android App says today I have 112 intensity minutes for the day, 36 moderate, 38 vigorous. 36 + (38*2) = 112. So...where did the extra 64 vigorous intensity minutes magically come from?
I bought this HRM-Pro while in Maui last month to get some swimming activity tracking, it has always behaved this way (moderate minutes fine, vigorous minutes inexplicable) but it seems it's the software or console that's really the problem, the actual activity the HRM-Pro is tracking is correct.
My work around? Give up on the Garmin sensor and user the Polar H10 that has always worked just fine, and the intensity minutes always match up. But, I can't do swimming activities with that to Garmin Connect, I can with Polar Beat though.
Other details: I have manually set up my intensity zones using HRR. Zone 1-2 = moderate, >= zone 3 = vigorous.
I have looked over the forums and can find nothing about this at all, I'm looking for anybody else that might have experienced this.