Yes, but I would not recommend mixing buttons from different generations. I daily experience issues (that the customer service doesn't seem to be interested in solving) where the hub doesn't fire some actions correctly when using gen1 and gen2 buttons in the same system with a generation 2 hub.
Do you happen to have any Flic1 buttons in your system? I have similar issues (with Philips Hue lights) when I use buttons from both generations with my hub. I.e. if I only use Flic2 buttons, then everything is OK, but if I press any of my Flic1s, then the hub seems to glitch out.
Sadly, the support for these products is terrible, and I haven't been able to reach anybody from shortcut labs for over a month, so I wouldn't get your hopes up that anybody will look into your issue either 
Hi,
In my setup I use the Flic hub, and a mixed set of gen1 and gen2 flics to control my Philips Hue lights. However, I have encountered a problem, where the programmed Hue actions are not executed correctly, when gen1 and gen2 button are clicked successively one after the another.
When used this way, the Flics require two clicks to execute the single click action. However, if only one generation of buttons are used to control the Philips Hue action, then this error does not occur, which makes me think this is an issue on Flic's side of things. In all cases, the click can be seen to be registered on the flic Mobile app, but the corresponding action is not fired correctly.
Steps to reproduce:
Version details
Hub FW: 2.0.14
I'm posting this here, since I never got a reply via the normal support email/support helper questionnaire thingy.
I hope you are able to address this issue with these instructions.