I guess that there's a bug causing MusicBee to remove the space before the centred dot when using "color" clauses,
since the album sub-header fields are displayed correctly (with space, dot, space) without "color" clauses.
Until correction of the bug, there are 2 options:
(1) Use one integrated virtual formula:
{font: Segoe UI Symbol;Regular;10}{contrast: 100}{color: 0,118,59}<Year>{color: default}" • "{color: 176,0,0}<Grouping>{color: default}" • "{color: 0,0,220}<Genre>
(2) Go on using the 3 virtual formulas, but append the following at the end of each:
In this case, the dot is not exactly centred, though.