Hi and thanks for the report! Being unable to craft a Hazmat Suit after learning the Plan for it is currently a known issue that we're planning to fix in our next update.
This thread was added on October 14, 2019, with posts from Valseek.
Original Post
https://www.reddit.com/r/fo76/comments/dgrzj2/i_purchased_plans_for_the_hazmat_suit_but_cant_it/