[malvosenior]

This is such a great response and I've had similar experiences. As you become more senior you also get more managerial responsibilities which can eat into your time/energy budget to stay up to date on tech not directly related to your job. You may also get more life responsibilities as you age (family...) that further erode your technical edge.

Good on you for having the introspective skills and awareness to identify the problem and do something about it.

[wuliwong]

I don't understand how this is a problem? If OP is a Senior Dev and interviewing for another Senior Dev role, wouldn't you assume that this new role is probably going to require similar skills to perform similar managerial type responsibilities?

I mean, sure go ahead and prepare for interviewing, brush up on whatever you think will help. But if a company has a policy of consistently rejecting candidates based on testing of skills that are never used on the job, it sounds like there's a lot of room to improve that interview process.

[malvosenior]

A lot of time people will move to a new job for a more senior position than their current job. Being a Sr. Engineer at a Series A funded startup can be very different than being a Sr. Engineer at Facebook (not always, but often). I would expect a higher bar at a larger engineering organization.

If someone is effectively testing for these more difficult subject matters then it's quite possible that they themselves and other co-workers are competent in them (as they passed the same test).