Puzzled, works with encoder disconnected

[troubleshooter]

I am unfamiliar with this product, and tried wading through the documentation.
I did not see an answer to this mystery;

Have a roboclaw, running an actobotics servo motor, controlled by an Arduino UNO.
brown encoder wire fell off, supposedly encoder B.
I still appear to be able to change preset speeds.
I reconnected it, no perceivable change.
So I tried disconnecting yellow, encoder A, also, since it was still conceivably getting a count (both disconnected now); still works!!!
How is this possible?

Is Roboclaw configurable by motor current and/or voltage? or by doing speed control (calculations) by these values?
I could not tell from browsing the documentation if that is possible.

I did not build this thing...

[Basicmicro Support]

If the PID is doing little or nothing(primarily a very low or 0 I setting) the feedforward argument(QPPS) will control the motor. This effectively runs the motor using voltage control without feedback. This will not give you accurate speed control but it may look like it is(especially under no load).

1. Fix your encoder wires. You will need both a and b channels on the encoder connected for proper speed control.
2. Tell me your PID settings for that motor.
3. Did you manually set them or use the autotuner?

[troubleshooter]

Thank you so much!

UPDATE 7-19-19
THANK YOU for the phone support,
I'm probably good for now.
I'll leave the below in case others want to comment or read it.
I think you have the answered my questions below...
[Arduino UNO guidance still needed, but perhaps more appropriate elsewhere]
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Would this also account for the ability of the Arduino UNO to change the motor speeds despite the loose wire?
(that was the part that seemed weird, and I concluded it must be regulating by voltage only, or by current or a combination of those).

And yes, speed stability is one of the issues I am fixing for the client.
(record lathe application)

Is there a way to verify resolver closed loop function, and not fallback speed control is in operation?

I did not build this, I am repairing all the mistakes made, and I don't have the source code.
I am also am unfamiliar with these products, but I am excellent in understanding and diagnosing most technologies. (I mean I am very familiar with these technologies, just not these specific products).

Thank you for your assistance!

[EDIT, sorry, started mixing my Arduino questions, with my Roboclaw questions here]
Are these (any) instructions and/or modes stored in the Roboclaw controller, or are all the parameters and mode instructions in the Arduino UNO? (single serial connection).

I will post in Arduino forum about the flash memory storage, unless you happen to know if are there 'de-compilers' that could let me view the Arduino instruction coding? (I mean, view the hex as RISC instructions and arguments/data fields)
I am pretty good with machine level code.

Mr K L

[Basicmicro Support]

You can use the Speed error setting to set az maximum allowed speed error. This should catch a problem like the one you had.

Settings are initially stored in RAM. You can use the Write Settings command in the Device Menu you write the settings to non-volatile memory on the controller once you have everything setup the way you want. These settings will be loaded each time the unit powers up.