Confirmed:
this due to bs5 which has the scss

// File input buttons theming
  // stylelint-disable-next-line selector-pseudo-element-no-unknown
  &::file-selector-button {
    padding: $input-padding-y $input-padding-x;
    margin: (-$input-padding-y) (-$input-padding-x);
    margin-inline-end: $input-padding-x;
    color: $form-file-button-color;
    @include gradient-bg($form-file-button-bg); = > gives `background-color: #132f53;`
    pointer-events: none;
    border-color: inherit;
    border-style: solid;
    border-width: 0;
    border-inline-end-width: $input-border-width;
    border-radius: 0; // stylelint-disable-line property-disallowed-list
    @include transition($btn-transition);
  }

Fixed in 2ea201f