Probably or maybe because of the different names ? One is Johnston and one Johnstone, looking at the Bio Johnston probably is the correct one, so to prevent it will be merged away into wrong LNAB Johnstone it probably has PPP ?
And noticed the Johnson name study and a lot of them are PPP 't so maybe all profiles part of the name study were PPP't ?
It's a bit confusing indeed because the earlier generation all have Johnstone for LNAB and are PPP't as well.Could use more sources to make it more clear and to know what LNAB is and what isn't correct .