I haven't heard such a comment either, but people don't generally talk to me about such things. However, https://www.fujirumors.com/now-panasonic-explains-whats-not-good-ibis-looking-forward-fujifilm-x-h1-ibis-anyway/Oly introduced IBIS very early, Panasonic were much later to the game because (so the cynics said) they wanted to protect their ILIS lens market. Olympus trumpeted their IBIS and how it was so good they did not need the cost and weight penalty of adding IBIS - then they added IBIS to their 300mm f4: the cynics said that to sell enough copies they had to do this to make it appealing to Pana owners who had bodies without IBIS.
Then Pana developed IBIS and both companies came out with hybrid IS that made all systems even better.
And as far as I am aware, in 10 years since MFT was introduced I have never heard a single comment about the fragility or unreliability of IBIS systems.
There are plenty of complaints out there from people with IBIS and people with IS who have had problems. I have personally not had a problem and have not had anyone tell me about a problem they have had either way... but my personal experience would only be anecdotal anyway.