Attacks were carried out by both sides in the final hours of the war, mostly in efforts to gain advantageous ground before the armistice came into effect.

The armistice did not end the war, it was merely an agreed upon ceasefire to give both sides time to negotiate the actual peace treaty. Realistically, the war could have resumed at any point up until 28 June 1919 when the Treaty of Versailles was signed and officially ended the conflict. The Germans still had millions of men in the field despite their deteriorating military situation, as did the Entente.

As the Germans were at that stage fighting a defensive war in the face of the Entente's Hundred Days Offensive, it was advantageous to them to possess the more defensive ground such as high ground, river crossings etc. The Entente also recognised this and knew that if the fighting resumed, possessing that same ground would provide them with an advantage. British troops attacked German positions at at a crossing on the Dendre River in order to secure the positions in case the fighting resumed.

There is also a stroy about an American Major General ordering an attack on a German held town hours before the armistice because he heard there was hot water and he wanted his men to be able to bathe. I haven't seen reliable sources on that story so it may be apocryphal but it does speak to the fruitless waste of lives that resulted from the many last minute attacks launched before 11am 11 November.