Hi Volker, I noticed that phab:T110555 had been assigned to you, so I assumed you were the best person to ask this question to:
After the mw-ui-constructive (green) buttons had been turned to mw-ui-progressive (blue), I noticed that, when a button created with w:en:Template:Clickable button 2 (which uses the mw-ui classes) links to the page it is on, the mw-ui-progressive buttons are a darker shade of blue (which is normal); however, the mw-ui-constructive buttons are a darker shade of green with a blue border. Is this intentional? (See w:en:User:CabbagePotato/sandbox2 for a demonstration.)