Should I be gluing some parts in my alternator?

In this case it does matter. If an alternator fails, well, it's a self-contained unit so typically replaced as a whole. But on the 'strom you can replace/fix your rotor, stator and regulator/rectifier independently of each other. So knowing what component failed (since it's a DL650 I suspect the stator) can help us answer your question better.

The DL1000 2003-later rotor is a six-magnet (permanent magnets) rotor. These tend to come loose over time, bunch together and severely reduce the charging voltage. Occasionally they also hit the stator causing massive destruction. Putting a JB Weld "bridge" between the magnets is an easy fix and should really be done preventatively on all 2003+ DL1000s. However that applies to the DL1000 only. The DL650 rotor is fully encased in epoxy (?) and I have not heard of any issues with a DL650 rotor ever.

The stator is a known weak point of all Stroms. Mostly because the default R/R is a shunt regulator so any excess charging current is "fed back" (someone correct me on the terminology here) into the stator causing high amps and eventually burning/charring/shorting of wiring. Keeping your oil level high helps a bit (the stator is partly oil-cooled) but the best upgrade would be to a series regulator such as the SH775 or SH847. Another reason that some stators burn through prematurely is that Suzuki used hot-melt glue to glue some components in place, and then applied the (anti-vibration) epoxy over it. The hot glue eventually melts, exposing the wiring to vibrations. Other than a visual inspection every now and then, the stator tests as described in the manual, and upgrading to a series regulator, there's nothing you can do preventatively to the stator.

The regulator/rectifier is a self-contained unit as well, and not user serviceable. It works until it breaks. There is a diode test in the manual to see if it still is OK, but if it isn't, you've got to replace it as a whole.

Long story short: On a DL650, other than replacing your R/R with a series regulator, there's nothing you can do preventatively to maintain your charging system. On a 2003+ DL1000 it is highly recommended to do the JB Weld bridge fix, to make sure your magnets cannot migrate.

To detect charging issues early, install a voltmeter if your display doesn't have one by default, learn the normal voltages for your bike and investigate any deviations.