I recall that these channels transmit program format aspect data. Set both the STB and the display to auto and these channels will switch aspect with the programming.
For testing, my monitor is set to auto resolution and auto ratio. The Amiko mini HD265 is set to auto display mode and auto aspect mode.
Currently:
Decades is showing proper ratio with window box of old 4:3 tv show.
Both H&I channels are showing proper ratios. 3976 has 4:3 window box of old tv show. 3953 was 16:9 full screen of Hillstreet Blues and now 4:3 with an 80's tv show.
Movies! Is showing 16:9 full screen movie.
Usually odd ratios and resolutions are if the broadcaster sends faux 16:9, doesn't send program aspect data or either/or the STB/monitor have aspect/resolution manually set.