Power cuts, faulty spotlights, overheated swimming pools and insufficient air conditioning were among the problems plaguing key test runs at the Rio Olympics facilities, highlighting persistent challenges three months before opening day.
But the international gymnastics, swimming and shooting sports federations, along with the Rio 2016 organizing committee, insist that the test events "went well overall," and that everything will be ready for the Games.
Andre Gueisbuhler, who heads the International Federation of Gymnastics (FIG), said five power outages lasting 15-90 minutes caused delays in both training and competition.
One of the outages that took place during training "endangered the safety of athletes," he added, without providing further details.
Another took place just before the French and Belgian women's artistic gymnastics rotated.
"I never saw a delay like that in the European or world championships," said a member of the French delegation.
"In the end, the girls made it out okay, but it's really a pain when the training is timed and you've set an entry at a specific time in your mind and body."
The outage was due to a cable that broke due to construction work around the site, Rio 2016 sports director Rodrigo Garcia explained.
The day of the 50-meter freestyle swimming competition final, which saw Brazilian star Cesar Cielo eliminated, an outage with projectors triggered a nearly hour-long delay. Similar electricity problems had already taken place during diving competitions in February.
An overheated generator was blamed.
"The risk of this happening again during the Games is zero, because we will have a dual power feed system, Garcia said, adding that there has only been one generator so far to reduce costs
With Brazil in the grips of a deep economic recession, about 20 percent of Rio 2016's operational budget was cut.
It was also very hot on the lower levels of the aquatics stadium, which became a sauna of sorts.
"Temperatures during the Games will be completely different, since it will be (the Southern Hemisphere's) winter."
Temperatures average 25 degrees Celsius (77 Fahrenheit) in August in Rio, down from 30 in this unusually warm month of April.
"The stadium is completely covered, and it's important to have artificial ventilation on the lower levels," FINA swimming federation executive Cornel Marculescu told AFP.
"We spoke with Rio's Mayor Eduardo Paes, who told us he would work on it. We will keep a look, come here, stay in touch with organizers."
In fact, negotiations are underway, with the mayor's office intent on controlling its budget and refusing to finance additional equipment.
"I chose to arrive early enough to train properly, but I was disappointed because the shooting range is not completed and installations are not totally ready either," said a disappointed Delphine Reau, a double-medallist for France.
The ISSF federation for shootings sports listed problems with organizers, pointing to "incomplete constructions, lacking air conditioning and lighting problems," its secretary general Franz Schreiber told AFP.
Nonetheless, a new world record was set in 3x40 men's rifle shooting.
"There was no air conditioning, and we all suffered in the heat of Deodoro" Olympic Park," Brazilian shooter Felipe Wu told the Globoesporte sports website.
"A Chinese Olympic champion (Du Li) wasn't able to finish the competition. She got sick and dizzy, and they had to take her away in an ambulance," Wu said.
"But such things happen. For a test event, it's better to get it wrong now so that everything can go well later."