What came next, was assumedly not what Joanna anticipated.
"You made a comment as though you had no care in the world for your sister-in-law," one angry Instagram follower commented on the post.
"It was the inability to show compassion and humility that caught the attention of your followers because however close you might be now with your husband and his family, another in very similar circumstances was suffering," they continued.
Joanna's most recent admission comes after she shared a photo of the annual Burgess family Christmas lunch, captioning the picture "was the best one yet."
Fans were quick to point out that Phoebe was absent from the picture, prompting many to write that she was taking an obvious swipe at the WAG. Joanna later clarified that it "is not in my nature to take a dig at someone."
"Phoebe has never joined the Burgess side for previous Christmas festivities. Therefore it couldn't possibly be aimed at her," she said.
"My last year's Christmas upload I used a similar caption as it was our son's first Christmas. This year we had our daughter join the three of us, hence it being the "best one yet'," Joanna signed off.
Things between the Phoebe and Joanna seem to have been hostile for some time now. Phoebe recently unfollowed both she and her husband on Instagram. Shortly after, Joanna did the same to Phoebe.
In recent weeks, reports have surfaced that Sam and Phoebe split during the holidays, three years after tying the knot in a beautiful Southern Highlands wedding.
"They tried to keep it together, but it all went to s**t, that's the honest truth," a source told The Daily Telegraph, adding that relations between the NRL star and WAG have been "bad for a while."
The insider also explained that Phoebe was taking the break up particularly hard as Sam's mother, Julie was supporting her son.
"It would have been hard for Phoebe because Julie would have completely stuck by Sam... and there's talk she didn't offer Phoebe much support,' the source revealed.