We have mixed to some extent SHC824 with r&O oils Amokon and Chevron GST46.

There was initial test data provided to indicate these would be compatible.

Would it be plausible that some kind of preciptate would form as a result of this mixture at the stagnant location at the pin area between equilizing pads in a Kingsbury thrust bearing?

electricpete,
I hope that the compatibility was confirmed by the ASTM D 7155 test method, or by a procedure very similar to what this ASTM method prescribes. Can you tell who did the testing, if you are permitted to disclose this info? However, I would not expect any precipitate being formed with new oil at the pins area you mentioned, providing there is no water and a layer of sediments (sludge formed from mostly wear and moisture) being settled there over the years of service. Very unlikely, but feasible, the new oil may be incompatible with such (settled) sediments, and possibly develop precipitate. Best way to find it is to test the oil, and compare if with new oil to see if any of additives reacted out of the solution and dropped out.