HI, CRCulver! 
My name is Kate, and I’m a mapper on the OSM team at Lyft. 
I made the decision to change the “lanes” tag for this short segment based on aerial imagery. According to the Lyft-owned street level image taken from Chapman Avenue in Dec '23 (33°47′20″N, 117°54′11″W). 
https://drive.google.com/file/d/1LUjFOh8WKfNRN-ep4PNSziYDOawdG08C/view?usp=sharing there are 5 lanes and no evidence of lanes count changes.
If you have more actual information about the road situation in this segment, I would appreciate it if you share it with me, and then I will correct my edits as soon as possible. 
Could you please explain in more detail exactly how the potential bugs that occur in Osmose may affect further mapping?
According to the OSM wiki there are no strong instructions that it is necessary to use tags ‘lanes:forward=*’ and ‘lanes:backward=*’  in combination with the lanes count tag for bidirectional roads -https://wiki.openstreetmap.org/wiki/Key:lanes#:~:text=in%20addition%20to%20the%20lanes%20tag. 

Best regards, Kate.
