“Large DTFlex prints that cover a lot of the garment feel plasticky and won't be breathable”

Transfer Kingdom (Source 3), the only non-claimant source, says very large solid DTF designs "can feel less breathable", which is weaker than "won't be breathable". It also says nothing about a plasticky feel and covers DTF in general rather than Printful's DTFlex. The exact wording ("feel plasticky and won't be breathable") appears only on Printful's own blog (Source 1), and its help center (Source 2) calls breathability "relatively low". Both are the claimant, so they show the claim was made but cannot confirm it.