First "A" on the lane is white, and the it's followed by two more yellow ones. Signs with bus symbol are also a mix of white and yellow ones. But look to me as permanent installations.
As I understand bus lane ends at bus stop Itas Kozakevičas iela.

I've gone ahead and tagged this lane. Can be seen here: https://zlant.github.io/bus-lanes/#15/56.9515/24.2042

Is the some official list from the city of designated bus lanes?