Will I have issues re-entering Thailand from Cambodia on a 60-day visa?

Depends on your travel history in the last 12 months

You will need to go to immigration and get a re entry permit. Once they stamp you out at immigration it cancels the visa without a re entry permit

If you're on an actual tourist rather than a visa exempt stamp and will return to Thailand before that 60 days runs out it may be possible to get a re-entry permit to keep your current stamp alive. Otherwise you can just leave and return. Whether you will be allowed to enter Thailand again will be at the discretion of the immigration officer you stand in front of, generally they look at your entry history over the past 12 to 18 months and if you've spent a lot of time inside Thailand in that period can deny entry. Make sure you have accommodation booked, a ticket out and 20k baht or equivalent in cash

If you are on a proper tourist visa you should get a re-entry permit.

When you have the METV it's not necessary.

If you are on visa exemption, you can leave and come back but won't get new 60 days.