Group email addresses for Teams sometimes contain “+” or “/” characters

We are using Microsoft Teams in our organization.

When creating multiple Teams with exactly the same team name, using ASCII alphanumeric characters only, we occasionally see that the automatically generated group email address contains unexpected characters such as “+” or “/”.
I would like to know whether this behavior is expected or if it is specific to our environment.
This issue seems to have been occurring since around August 2025.

We manually create Teams using the Windows Teams client.
For example, if we create several Teams with a simple name such as “example2026”, the corresponding group email addresses are generated in the following format:

email address removed for privacy reasons

However, in some cases, the XXXXXX portion includes characters like “+” or “/”.
When creating around 50 Teams, this issue appears in a few of them.
This causes two problems for us:

• A “+” character interferes with plus-addressing behavior.
• When a “/” is included, we cannot create events inside the Team.

Has anyone else encountered this issue or knows why this happens? Any insights would be appreciated.