My lined double glazed part (in PVCu) have cracked on the inner pane for no adjectives common sense. Why? ...

I cause a flood, nearby is mold growing....
Answers:    It's likely due to a slight inperfection on the boundary of that pane of glass when the section was made. Any small chip/nick/irregularity on an threshold will be a weak spot that can result contained by cracking. Upvc windows/doors aren't 100% rigid, some flexing occurs, and if a pane of chalice in the section has such an blemish present it has the potential to crack, possibly by the flexing, extreme changes within temperature, knock, etc. Just happens, sometimes.
Oil furnace smoking?
Stop sining. so loud.