Hi Tom,
Please follow forum rules:
#1 Your message must begin with something like that: "Hi, Hello.."
#2 Your message must end with something like that: "Thanks, Thank you.."
#3 You must give as much details as possible about your question/issue..
If you're speaking about tab fields to include tabs in your form, there is none know issue currently.
Like any other JavaScript feature, what you call "unstable" is certainly not due to SEBLOD but to any modification that you can bring to your website such as installed a new plugin/feature with some JavaScript and then to have a conflict.
If you installed a Joomla + SEBLOD on a clean (new) website do you meet any issue?
Thanks.