Cards resist being typed as Number.
I added +Hours to the structure of card type "Task", entered the rules to change the default of all +Hours to type Number, and recieved the error:
' is not numeric
It does not matter what appears in the card, or if the card is being originated and has no content of any kind. Still " ' is not numeric."
I even erased everything at the HTML level. Still ' haunts me.
What are you changing it from? If it's a Basic card, it may have html tags around it (eg <p>.25</p>).
Yes, Wagn should strip that when you change it to a number, but alas, it does not yet.
Workaround is to change to a phrase or plaintext first, clean the data, and then change to a number.