I totally see what you mean. This happens on my side too.
The selection caret doesn’t activate until the right side of the first character.
I notice that if I move the caret to the line I want to select from, then the caret can be moved to the left side of the first character. But that is touchy and slow.
Notice in this gif that when you move the caret from line to line, the arrow shifts slightly. I think this would be worthy of a bug report.
Here is a somewhat related Feature Request, about selecting from the left margin/gutter.