If it were me, I would clear RB1 to a zero at the start of the program and leave it that way. I see no sensible reason to keep disabling the clock, and I wonder whether this might actually be causing spurious clocks.
Hard to be sure without real hardware to test with.
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Now I think harder about it, then all clocks need to be enabled at all times, else how will the data circulate around all shift registers?
Leave all CLK_Inhibit lines low at all times. Ideally tie them low with hardware and use RB1 for some other purpose.