I've set up a a testworld, with Angels-Infinite ores without fluid requirement and one with fluid requirements.
I guess you refer to the displayed Ore/s in the miners interface (When you click on it, with the progressbar and module slots) and not to the notes when only hovering your mouse above it?
There is one thing to know: I didn't write specific mining code. This mod uses the vanilla mining code.
So I've also set up a vanilla miner and used this https://www.reddit.com/r/factorio/comments/az3tlj/belt_throughput_counter/ei7837z/ blueprint for measuring belt throughput.
With activated fluids the shown mining rate (plus 40% mining productivity) matched with the measured throughput.
However and you observed the same as I did: Without the fluid requirement the Vanilla Miner showed (0.8 - 2.3 /s) [that number is before mining productivity] and the measured throughput was 0.7/s [including mining productivity].
On the Bucket Wheel Excavator (Mk. I) there was a similar pattern happening (26 -141 /s) shown, but throughput wa 21/s.
Last but not least I removed this mod from the testworld and the Vanilla Miner stayed at the same throughput, which is much lower than the displad mining rate.
In conclusion: This is a vanilla (display?-)bug.
