Learn English – How to use a phrase to describe a situation that you meet a problem can’t be solved

That is called cocking your head:

to set or turn up or to one side, often in an assertive, jaunty, or significant manner:

metafilter has an interesting post regarding the function that head-cocking can serve.

Others may disagree, but I think "glitch" might fit.

• "one minor glitch". and if you're sure it's fixable, say "fixable glitch" .

• If you think the program could be put into use despite the problem, say "it's not a show-stopper".

• If the problem can be documented around, it's "not a bug, it's a feature" (that's an IT joke; not one you would tell a customer.) But seriously, if users could be trained to work around it, "it's a training issue".

• If it's a feature that was in the spec, but can't be delivered in this release, say that it "won't be in the initial rollout", but that it (i.e. getting it working) is "on the wish list for Phase Two".