I overpaid for this... IBM Model M ashtray, for the lack of a better word. I looked at pictures of the internal assembly online, and I think there're missing springs? For example, I can't press the upper half of the enter key because there's just no spring there, not even blue placeholders. I can't exactly buy new springs from Unicomp as the shipping is so prohibitively expensive that I could buy a IBM Model M from someone else.
https://www.clickykeyboards.com/product/ibm-buckling-spring-assembly-set-of-10/
Also, read the fine print:
Still costs $2.00 + $35.20 shipping + $7.44 import sales tax = $44.64, though. I was too impatient when I bought my IBM Model M. I even saw one get sold for $35.
Try emailing them to see if they'll ship a small amount to you for cheaper.