Wrong tag associated with expression?

[jmandel]

Describe the bug
When I use tags with optional expressions, the wrong tag is sometimes assigned to an expression

To Reproduce

Reproduction at https://pest.rs/?g=N4Ig5gTghgtjURALhAUwB4AcIAIC8OwAOgHY44DKA8gJI4B%2Bp5AxFCQMYAWA9hHgBQUAKgEEASgEoA-AxzMAzgFcAZsoCW6PABEqQqU1kBRWqQC%2BpUsPF5iIAFREQ5kjqE3HAOkfOQAGhBqJJiKAC7I9k5AA#editor

1. Parse * as a expr in the example grammar

expr = {
  SOI ~
  #prefix=(STAR)? ~ #suffix=DOT?
  ~ EOI
}

STAR={"*"}
DOT={"."}

Expected behavior

- expr
  - (#prefix) STAR: "*"
  - EOI: ""

Observed behavior

- expr
  - (#suffix) STAR: "*"
  - EOI: ""