You have it framed incorrectly, omitting a T, to wit, from Genbank entry:
23581 ttatcagact cag act aat tct cct cgg cgg gca cgt agt gtagctagtc aatccatcat
So no stop.
Also, it is the third base, the wobble base, that is consistently mutated over time in a highly conserved, constant amino acid sequence.
I did make an arithmetic error, pointed out to me by email – the TMRCA is 38.5 years between Bat RaTG13 and the novel coronavirus. Still far too long a time for Bat RaTG13 to be a proximal source.
I stand by my analysis.
Bill Gallaher