They really need to share more details of these term sheets that fell through so we can confirm they were either binding or signed.
"Term sheets are non-binding, and even though they should signify a VC has conviction in investing in you and is ready to move towards closing, they fall through more often than most founders may expect." - https://techcrunch.com/2015/05/22/three-reasons-your-term-sh...
If these were signed term sheets and the investor has done a few weeks of legal / financial due diligence - then yes - not common. If these are deal or talking point term sheets with no definitive agreement and little formal due diligence - then those do fall away more often.
"Term sheets are non-binding, and even though they should signify a VC has conviction in investing in you and is ready to move towards closing, they fall through more often than most founders may expect." - https://techcrunch.com/2015/05/22/three-reasons-your-term-sh...
If these were signed term sheets and the investor has done a few weeks of legal / financial due diligence - then yes - not common. If these are deal or talking point term sheets with no definitive agreement and little formal due diligence - then those do fall away more often.