1955 Roosevelt Dime DDR

Proofs are typically struck two or more times. I have seen Hundreds of proof coins where the 2nd strike was off. Some of the off 2nd strikes were almost visible to the naked eye.
Its a confusing grey line when you talk a legit 2nd strike for a proof coin, and say, a "double struck" proof which is probably one that is WAY off.

A proof Doubled Die would be convincing if the object that was doubled actually showed the extra carving that makes it a doubled die. A Doubled Die coin is one that the DIE itself has the engraving error on it, not simply an additional strike of a coin.

Knowing that a proof coin can have multiple strikes, some of these DDO's and DDR's can DEFINATELY appear to be DDO's and DDR's, when they are not.

Since the die has the issue on it, the good thing is, some one else may have already found one like yours, if it is a DDO or DDR. Coneca Online may have documentation on your coins' year and whether a DDO / DDR exists on that denomination and year.