Whether any work assignment is normal or not, heavily depends on the sector / domain, the industry and finally, the organization policies. While a practice may be common in some cases, it might not be the norm in some organization, and vice-versa.
The real question is: are you willing to put your efforts into the work you don't really want to do or enjoy doing? Whether it's normal or not, comes secondary to that.
In my experience, some (again, subjective) amount of field / production/ customer support is expected of the engineering team, but they come as a last resort or in case of high-to-critical priority tasks. For normal work items for field / customer cases, it's expected that a separate team will be allocated with professionals having enough knowledge and expertise to handle majority of the work items / tickets and only the cases requiring specific expertise will be reaching to the engineering team via an escalation method.
If field / manufacturing / customer support becomes a regular thing, and either the engineering activity is delayed / interrupted with those work requests, there are two things that needs to be done:
- Talk to your manager about the volume of request you (and the team) is receiving and ask for their opinion (on how to handle those requests, setting priorities etc.)
- Ask to have an escalation matrix prepared, where before a case reaches the engineering team for help, a proper tracking is available where the previous efforts are logged and the problem statement is clear, so the engineering have to spends minimal effort in reproducing the issue and can focus on getting the solution out quickly.
Finally, if actually the support load is higher than the existing manufacturing / field support team can handle, there might be a need to increase the team strength / capacity - but that can only happen when the amount of work is formalized and tracked through the escalation.