Will Allah not forgive someone on days of mercy, such as the middle of Sha‘ban, if they commit a sin on that day?

On the night of mid-Sha'ban, Allah forgives all of His creation except for a polytheist or one who harbors malice (mushahin). The mushahin is: one who harbors hatred and enmity towards a Muslim without a religious reason, or an innovator who separates himself from the community of the Ummah.