Take a look at what I wrote here. Although that post started with an issue with Hue lights, it’s not limited to that brand. Switching multiple devices from the same flow just doesn’t work very well.
Because the Hue bridge (and the IKEA gateway too, if I remember correctly) supports grouping, you may be able to get it working properly if you buy one of those, create groups of bulbs (which you cannot do from Homey, so you’ll need to use the official Hue of IKEA mobile apps for that), and just switch a single group from Homey’s flows (that being said: using the Hue bridge comes with its own drawbacks, like delays in status updates).
