After taking over the race-leading car he shared with Julien Andlauer towards the end of the second hour, 2016 Le Mans 24 Hours winner Jani struggled to get the door shut as he rejoined the track.
This continued for several laps as he circulated slowly under the virtual and then full safety car before eventually Jani succeeded.
Speaking after a spirited drive to finish fifth, Jani said: "I don’t know what happened with that door, it was like the mechanism somehow got stuck and the door wouldn’t close anymore.
"In the end, I figured out that I had to pull the pin, pull the door, let the pin go, and then it closed. But I had to first push it in with my finger."
Remarkably, it was not the first time the Swiss had experienced a door problem with a prototype in racing conditions. Jani believes he missed out on a podium at Le Mans in 2018 when driving Rebellion's ORECA-built R-13 LMP1 due to a loose door.
The team was not confident it could be shut if opened again, which forced him into driving the final three hours solo and incurred two penalties for exceeding stint lengths as a result.
Asked by Autosport if the problem was something he would talk to Porsche about to prevent a future recurrence, he replied: "Yeah we have to look at it mechanically.
"It’s too early for me to say what the problem in the end was, but clearly there was an issue.
"I had the same issue in Le Mans with the Rebellion and we lost the podium.
"Okay, it was only between P3 and P4 with the Rebellions [with Toyota taking an unchallenged 1-2] but it happened to me already once and it can happen, it does happen."
Jani joked that "I would have cried" if it had occurred under green due to the car's strong pace at Spa, "because afterwards we pulled away, and we actually were like 'okay, we’re back in the race here'".
Running third after being overtaken by the two factory Ferrari 499P Le Mans Hypercars, Jani was coming under pressure from Earl Bamber's Cadillac V-Series.R LMDh in the fifth hour when the Kiwi clipped Sean Gelael's WRT BMW M4 GT3 on the Kemmel Straight to send both cars crashing heavily into the barriers.
Pitting shortly before the resultant red flag vaulted the winning #12 Jota and #6 Penske Porsche Motorsport Porsches into unassailable positions following the restart, while Andlauer produced several eye-catching moves at the Eau Rouge/Raidillon complex to recover fifth behind the Ferraris.
Without the red flag, Jani was confident that "the podium for sure was ours".
"Would we have won? I don’t know," he said when asked if a victory was possible.
"But for sure finished third, that is clear, it would have been between us and the Ferraris.
He later added: "In terms of pace, we would have deserved to win as well."
