Part of the issue could be what they look up in TIMATIC. The relevant information only shows up when "China" is entered in the transit field - even if "China" is
also entered in the destination field.
Visa required, except for Nationals of <visa exempt nation> holding
confirmed onward airline tickets to a third country, if
arriving in and departing from the same city:
- at Changsha (CSX), Chengdu (CTU), Chongqing (CKG), Dalian
(DLC), Guangzhou (CAN), Qingdao (TAO), Tianjin (TSN), Wuhan
(WUH), Xi'an (XIY) or Xiamen (XMN) for a max. transit time
of 72 hours, starting from 00:01 on the day following the
day of entry.
- at Beijing (PEK), Guilin (KWL), Harbin (HRB), Kunming
(KMG), or Shenyang (SHE) for a max. transit time of 72
hours;
Visa required, except for Nationals of <visa exempt nation> holding
confirmed onward air, cruise or train tickets to a third
country, arriving and departing from any one of the following
locations: Hangzhou (HGH), Nanjing Lukou (NKG), Shanghai
Hongqiao (SHA) or Shanghai Pudong (PVG) for a maximum of 144
hours, starting from 00:01 on the day following the day of
entry. (SEE NOTE 75232)
NOTE 75232: This also applies to passengers traveling
from/to Shanghai Port International Cruise Terminal,
Shanghai Wusongkou International Cruise Terminal and
Shanghai Railway Station.
- All transiting passengers are subject to a check by
immigration. Passengers in transit must hold passports or
passport replacing documents that are accepted for entry
into China (People's Rep.). For more details on document
requirements, please enter China (People's Rep.) as a
destination.
- This does not apply at Beijing (PEK) if staying in the
international transit area.