Yes, that is a typo in the 5.2.0 release notes. It should say:
"MEME motif text format: Now allows "P= <motif p-value>" in place of
"E= <motif p-value>" on the letter-probability matrix line."
Thanks for pointing that out.
This change was made for STREME, which reports adjusted p-values for the motifs it discovers
rather than E-values.