The compound presented here is, however, not an organoaluminum compound. Those have Al-C bonds and are indeed very reactive. Aluminum formate has the Al3+-ion coordinated only by oxygen, and will certainly not exhibit the reactivity you described.

Chemist here.

Formate does indeed act as a reducing agent under appropriate conditions, but its byproduct is typically CO2 gas, not formaldehyde (HCOO- -> CO2 + H+ + 2e-). Aldehydes are generally unstable with respect to disproproportionation and are therefore unlikely reaction products.

Organoaluminum compounds are molecules with direct Al-C bonds, whereas these are effectively normal ionic salts with some unusual unit cell structure. Conflating DiBAl with aluminum formate is akin to conflating chlorine gas with clhoride anion...

Formate ions can disproportionate:

HCO2H -> CO2 + H2

HCO2H + H2 -> HCHO + H2O

However, aluminum salts of formate are likely more stable? You usually need formic acid and heat to generate hydrogen.

also if you get trace amounts of formaldehyde out the smokestack it isn't going to last more than a few hours in the environment. every living thing produces formaldehyde