Layout Builder not setting column sizes on front end

On our web site Layout Builder widgets are not getting column sizing applied correctly. Under normal circumstances, they’d have a style like this applied:

#pgc-w597c91d417684-0-0, #pgc-w597c91d417684-0-1, #pgc-w597c91d417684-1-0, #pgc-w597c91d417684-1-1, #pgc-w597c91d417684-2-0, #pgc-w597c91d417684-2-1, #pgc-w597c91d417684-3-0, #pgc-w597c91d417684-3-1 {
    width: 50%;
    width: calc(50% - ( 0.5 * 50px ) );
}

However, that code is just not there. If you re-save the page and refresh, those styles miraculously reappear, but they disappear the instant you refresh.