Strange Replace problem within RuleDelayed within function

Question

I've run into a strange anomaly with Replace when it is performed inside the first argument of RuleDelayed within a function that includes one of its parameters as the second argument to the same RuleDelayed. Obscure, I know, and I can work around it, I'm sure, but it has me scratching my head.

Replace is finding a match, but is unable to utilize the pattern labels I provided on the RHS of the replacement expression. The problem goes away if I only replace at e.g. level {0} or if I don't use the function argument in the RuleDelayed... Any ideas?

See below:

ClearAll[ReplaceProblem]
ReplaceProblem[a_] := RuleDelayed[
  Replace[NotEvenUsing@AnyParameters, 
   f_[x : Except[_Pattern]] :> f[x]],
  a]
ReplaceProblemGone[a_] := RuleDelayed[
  Replace[NotEvenUsing@AnyParameters, 
   f_[x : Except[_Pattern]] :> f[x]],
  abc]
Column[#, Frame -> All] &@Trace@
  ReplaceProblem[a]
Column[#, Frame -> All] &@Trace@
  ReplaceProblemGone[a]

Output (bad version):

ReplaceProblem[a]
Replace[NotEvenUsing[AnyParameters],f$_[x$:Except[_Pattern]]:>f[x]]:>a
{{f$_[x$:Except[_Pattern]]:>f[x],f$_[x$:Except[_Pattern]]:>f[x]},Replace[NotEvenUsing[AnyParameters],f$_[x$:Except[_Pattern]]:>f[x]],f[x]}
f[x]:>a
f[x]:>a

Output (good version):

ReplaceProblemGone[a]
Replace[NotEvenUsing[AnyParameters],f_[x:Except[_Pattern]]:>f[x]]:>abc
{{f_[x:Except[_Pattern]]:>f[x],f_[x:Except[_Pattern]]:>f[x]},Replace[NotEvenUsing[AnyParameters],f_[x:Except[_Pattern]]:>f[x]],NotEvenUsing[AnyParameters]}
NotEvenUsing[AnyParameters]:>abc
NotEvenUsing[AnyParameters]:>abc

I seemed to have confused the automatic scoping rules somehow...? Where did I break some rule???