Can't open attached emails

[Ace Suares]

When receiving an email with some included (attached) emails (most of the time in 'htm' format), zimbra is unable to open these emails.
A new window opens, but it stays empty, and in the console it gives an error like 'TypeError: d not found'.

It looks like it's in the code for the zimlets but I am not sure.

Anyone else with this experience or a solution?

Release 8.8.9.GA.2055.UBUNTU16.64 UBUNTU16_64 FOSS edition.