A native notification for MAIN.Flags.3 / .ADSSTATE_RUN.0 was registered on the
literal WORD.N path, which ADS has no symbol for: live on the TC 2.11 Elma
cleaner Z33856 it failed with DeviceSymbolNotFound, and that registration
error tore down the whole subscribe call. The read path already reads the
parent word; the notification now does the same - it registers the parent as
raw bytes at its resolved width and reads the bit (TwinCATBitAccess), refusing
a bit outside the parent or a non-integer parent with BadTypeMismatch.