Irena's post comes shortly after her new man Locky, also 31, appeared to attend this week's Melbourne Cup festivities without her.
The former Survivor star shared a photo from Tuesday's event, but his fans and followers were quick to notice Irena's absence.
"I didn't see Irena with you," one mused.
"Missing Irena here," another wrote.
However some speculated that Irena, who has spoken publicly about her vegan lifestyle, chose not to go to the event for animal rights reasons.
"Irena is vegan so unlikely to support horse racing + be at horse racing events," one commented on Locky's photo.
"I love Irena a million times more now, knowing she didn't go to the cup in protest to animal cruelty," penned another.
Locky later confirmed that this was indeed the reason for Irena's absence, and joked that his girlfriend was probably “protesting out the front.”
“Being a vegan, [Irena] doesn’t like Melbourne Cup,” he told AAA.
Bachelor fans went into a frenzy this week when Rottnest Island Tourism congratulated Locky and Irena on their "engagement" in an Instagram comment.
However, Locky put the rumours to rest when one fan congratulated him.
"Haha no engagement here," he replied in an Instagram comment on his post.
When the fan referred him to the Rottnest Island Tourism comment, Locky replied once more saying: "Yeah we saw that as well but the phone flips photos and the ring ends up on the wrong side haha but thank you."
Locky and Irena have started to settle into their new life together in the WA capital and had to undergo two weeks of mandatory hotel quarantine together.
"It’s definitely been a tough few weeks. Trying to keep the happy emotions under wraps for that long has been really difficult because all I’ve wanted to do is scream and shout how much I love Locky," she revealed the morning after that final episode.
"It’s been hard but we got through it and here we are on the other side."