If you used vinegar to clean your washing machine approximately one month ago and then used bleach recently, there is a minimal risk of a chlorine gas reaction. The key factor is that you allowed enough time for the vinegar to evaporate and dissipate from the washing machine before using bleach.
Vinegar contains acetic acid, and when it comes into contact with bleach (sodium hypochlorite), it can produce chlorine gas, which is harmful if inhaled. However, chlorine gas is only produced when vinegar and bleach are mixed together simultaneously.
Given that you used the vinegar a month ago, it's highly unlikely that any significant amount of vinegar residue remains in the washing machine. Vinegar is a weak acid and will naturally evaporate over time, leaving behind only water and a small amount of residue.
As a safety precaution, it's always best to ensure good ventilation in the laundry area and avoid directly mixing vinegar and bleach or using them together in the same wash cycle. If you want to use both vinegar and bleach for cleaning purposes, make sure to run separate cycles and allow sufficient time between the two.
If you're concerned about potential residues, you can run an empty cycle with hot water and detergent to help flush out any remaining traces of vinegar or bleach before using the washing machine for regular laundry. As always, follow the manufacturer's instructions for cleaning and maintaining your washing machine.