iExists fails if goal after the existential quantifier is an evar

Iris version: dev.2019-11-22.2.a979391c

iExists fails if you have a goal of the form

∃ _, ?P

Here is a test case which illustrates the problem:

Lemma test Σ:
  (∃ P, ∃ (_ : True), P : iProp Σ)%I.
Proof.
  iExists _.
  (* Here iExists fails *)
  Fail iExists _.
  (* Solving the existential quantifier manually *)
  eapply coq_tactics.tac_exist.
  (* Using apply fails *)
  Fail apply @class_instances_bi.from_exist_exist.
  (* But apply: works *)
  apply: @class_instances_bi.from_exist_exist. simpl.
  eexists _.
Abort.