I’ve seen this sort of issue with the Pyramid when used with some other equipment.
Its not caused by a problem with the midi data being sent, its more of a midi electrical signal issue, caused by a hardware component tolerance issue, that causes some combinations of midi equipment not to receive messages. Its not usually the sort of thing to expect a firmware fix to be available for. People usually solve this sort of thing by using different combinations of equipment, for example by changing their setup plans entirely, or adding an additional midi device in between the two devices that dont like each other. For example some people solved Pyramid issues by using various midi thru boxes sitting in between the keyboards output and the Pyramids input. I think someone else got a Keystep to work with the pyramid by powering it via a power supply rather than USB.
I think there is a thread about this on the Pyramid forum, which started off with someones problem using the M-Audio Keystation, but quickly ended up including people mentioning other devices they had issues with such as the Moog Grandmother. I think much later in the thread someone even said they fixed the issue by replacing the midi in optocoupler (6n136) inside the Pyramid with the equivalent part from another manufacturer. So if people want to attribute blame for this sort of incompatibility, I would tend to blame the midi input circuitry on the Pyramid not working with some other devices. I dont remember with certainty which combination I had a problem with in the past, though it might have been the Polyend Medusa and the Pyramid.