Bootstrap v4.x Growing spinner show as blank in MacOSX/Safari

[asolis]

Growing spinners show as blank in Bootstrap v4.4.x, v4.3.x, and v4.2.x aren't displayed in MacOSX/Safari.

The issue is present in:
MacOSX ( High Sierra 10.13.6) with Safari (v13.1)
MacOSX ( Catalina 10.15.4) with Safari (v13.1)

*They do display correctly in both MacOSX versions using
Chrome (Version 80.0.3987.163 (Official Build) (64-bit))

While looking at the generated @keyframe spinner-grow CSS rule in Bootstrap v4.4, v4.3, and v4.2 .
They currently display the following:

@keyframes spinner-grow {
 0% {
      -webkit-transform: scale(0);
      transform: scale(0);
 }
 50% {
     opacity: 1; 
 }
}

Adding transform:scale(1) at 50% fixes the issue.

@keyframes spinner-grow {
 0% {
      -webkit-transform: scale(0);
      transform: scale(0);
 }
 50% {
     opacity: 1; 
     -webkit-transform: scale(1);
      transform: scale(1);
 }
}

The proposed changes were tested successfully under the mentioned MacOSX / Safari and Chrome version mentioned before. Below codepen reduced test case:

CodePen Reduced Test Case

[XhmikosR]

Duplicate of #30493