The gray slaad's Perception bonus is weird, but monsters are allowed to have weird numbers. Normally, it would be Perception +7, not +6.
— Jeremy Crawford (@JeremyECrawford) August 15, 2017
Errata? Gray Slaad have WIS 8 (-1) and Perception +6
The gray slaad's Perception bonus is weird, but monsters are allowed to have weird numbers. Normally, it would be Perception +7, not +6.
— Jeremy Crawford (@JeremyECrawford) August 15, 2017