Nintex for office 365 doesn't properly support html within repeater section. It has some issues. please see attached video.
For me it is clearly a bug, but Nintex support team is refusing to accept. They asked me to raised this as an idea. Nintex-OnPrem support html within repeater control. Nintex-Online is also working fine if we put html inside repeater, but only for initial rows. please see attached videos.
please see Nintex Support Case #00623216 for details.