Hi, I've read other posts about branding not saving, I have a similar problem. Saving via the Template manager breaks everything and takes it back to a default state.
I found that it's not the same in my local version, so I solved it by changing directly in the database the table "template_styles" for the takai template params to what I have back in local.
I solved it by hand, though I wouldn't like to do it like this every time I want to change something.
It seems that when saving, it saves all the fonts in a list of googlefonts and all, and it runs out of space for other data and even at the end it gets truncated

Edited: the data I wanted to post doesn't fit here, will upload a txt

Is there a way this can be avoided?

I can't add a file (.txt) to the forum :( tried with chrome and firefox

Please update the template its latest version and the issue will be solved.
Download the update package and install it through the Extensions manager like any other Joomla! extension or template.