Jelly, 18 bytes
J:g¥Ƭ’}ṪU×ḷb§¥ƬṪS%
A less naive computation of the digital roots comes out a bit longer by having to special-case 0. Inverted output: truthy (nonzero) if the checksum fails.
J 1-indices from the start
: divided by
g¥ their GCDs with
’} B - 1
Ƭ Ṫ repeated while unique,
U reversed
×ḷ times each N.
ƬṪ Loop while unique:
b ¥ Convert each to base B
§ and sum each.
S Sum
% mod B.