Cuddles:
2-year-old male, neutered in April 2026, recently adopted

Lucie:
2-year-old female, spayed in 2024, had since 2024

We are currently on Day 7 of 24/7 bonding as advised by our rescue. So far we’ve expanded the pen twice, it’s now around 2mx1m, we started off at around 1mx1m and overall things seem to be going well. They eat together, groom each other, rest together, and will often choose to lie next to each other. They also share enrichment without any issues.
The main thing I’m unsure about is Cuddles’ behaviour.

During the first 2 days of bonding, the mounting was very obsessive. He would repeatedly mount Lucie for hours at a time, with only short breaks in between. The rescue advised us not to intervene unless there was a fight or absolutely no breaks in the behaviour, so we let them work through it.
Since then, the mounting and chasing have gradually decreased. He still mounts and chases at dawn and dusk, but now it’s usually limited to a 5–20 minute period. During these sessions Lucie will run away and Cuddles will follow her, but it never escalates into a fight. Once he stops, Lucie often goes straight back to him to groom him or lie next to him, so she doesn’t seem particularly upset by it.

Over the last few days I’ve noticed a new behaviour. Cuddles will sometimes hop around the pen grunting. He also occasionally runs up to Lucie while grunting as though he’s about to mount her, but instead he grooms her head and back.
Yesterday he even briefly groomed and mounted her at the same time. Today he ran up to her grunting and then groomed her again.

Another thing I’ve noticed is that since we’ve extended, Lucie is often the one initiating stuff. For example, they’ll rest apart for a couple hours, then she’ll go over, groom him, and lie next to him. He accepts the grooming and they relax together.

My questions are:

Why is cuddles acting like this?

What does the grunting followed by grooming mean?

Is this normal bonding behaviour?

Does the bond sound like it’s progressing well?

Should we continue gradually expanding the pen, or should we wait until the grunting/mounting has completely stopped?

Should we decrease the pen until the grunting / mounting has stopped?