Contradiction with Zechariah 12:5
Zechariah 12:5 speaks of the leaders supporting inhabitants of Jerusalem, in contrast with the mourning in 12:11.
Zechariah 12:5: And the governors of Judah shall say in their heart, The inhabitants of Jerusalem [shall be] my strength in the LORD of hosts their God. [The inhabitants...: or, There is strength to me and to the inhabitants, etc]
Contradiction with Zephaniah 1:14
This verse talks about the great day of the Lord being near and dreadful, contrasting the specific mourning in Zechariah 12:11.
Zephaniah 1:14: The great day of the LORD [is] near, [it is] near, and hasteth greatly, [even] the voice of the day of the LORD: the mighty man shall cry there bitterly.
Contradiction with Ecclesiastes 3:4
Ecclesiastes 3:4 mentions a time to mourn and a time to dance, which highlights the broader spectrum of emotions compared to the specific mourning in Zechariah 12:11.
Ecclesiastes 3:4: A time to weep, and a time to laugh; a time to mourn, and a time to dance;