It is likely a question byte order of numbers, of "little endian" vs. "big endian" CPUs.
Is 0x0064 stored in two bytes as is "00 64" or as "64 00" ?
That was something that I speculated three years ago at
and like @jow summarized as
Your other part about NASID is similar:
Hexadecimal characters for 0-9 are 30 31 ... 39
So, if one takes ASCII string of "6334..." it is actually hexadecimal values as "36 33 33 34 ..."
Apparently OpenWrt and your other router handle that aspect differently.
Other router want just ASCII numbers as the NASID and then stores it (naturally) as hex character, while OpenWrt directly takes/shows a hexadecimal string in config.
Ps.
I use a byte-symmetric Mobility ID myself for 802.11r...
something like "0D 0D"