I've had the most pleasant evening trying to find research discounting your claims and instead having my beliefs whipped around by evidence (though I still don't understand how a neuron can be said encode in a purely reference independent manner given as with pain receptors' sensing thresholds for mechanical, thermal, and chemical changes or absolute pitch recognition).

One of the few sources my motivated cognition discovered was the work of Padoa-Schioppa, who found, for instance,

In the experiments, monkeys chose between different juices and their choice patterns provided a measure of subjective value. Value ranges were varied from session to session and, in each session, OFC (Orbitofrontal Cortex) neurons encoded values in a linear way.

Which of course seems another reference independent encoding, though there is just about as much evidence the other way on the subject of the OFC, such as Elliott (2008).