The term قیام متصل برکوع means pausing for a moment after recitation before going to the ruku.

According to the office Ayatullah Sistani (may Allah prolong his life)

1) It's wajib

2) if one goes to the ruku without the mentioned pause, they have to return back to standing position (qiyam) pause for moment then perform the ruku.

Also refer to the following issue will be helpful to you 

969. If a person forgets to perform Ruku, and sits down after reciting Hamd and Surah, and then remembers that he has not performed Ruku, he should first stand up and then go into Ruku. If he does not stand up first, and performs Ruku while he is bowing, his prayers will be void because of not having performed qiyam (standing) before Ruku (Qiyam muttasi'l ba Ruku').

https://www.sistani.org/english/book/48/2220/