Did the Appeals Court err by granting the Government's motion to enforce an invalid appeal waiver, after determining that Currys' issue was non-frivolous, and ordering the parties to brief on the issue?

QUESTION(S) PRESENTED 1. Did the Appeals Court err by granting the Government's motion to enforce.an invalid appeal waiver, after determining that Currys' issue was non-frivolous, and ordering the parties to brief on the issue? 2. Does a valid appeal waiver bar a Court of Appeals from correcting an unconstitutional sentence were the defendant's argument, if true, would mean the District Court lacked jurisdiction to sentence defendant under 18 U.S.C. sub-section 924(c)? , 3. Does the Court of Appeals lack jurisdiction to correct plain error, due to invalid appeal waiver? . : : 4: