The "abbreviated" names in the vcd file are silently truncated to 1 char. So, if your input VCD file looks like:
...
$scope module logic $end
$var wire 1 b0 pinB0 $end
$var wire 1 b1 pinB1 $end
...
#123
1b0
0b1
#456
0b0
1b1
...
you end up with only one pin being toggled with no indication that this is happening.
The "abbreviated" names in the vcd file are silently truncated to 1 char. So, if your input VCD file looks like:
you end up with only one pin being toggled with no indication that this is happening.