Your Answers lies in your question itself . Still i will answer your last statement , If you see many bars of beam in column then
Following precautions can be taken
Provide proper covers
Check water tightness for shuttering
Proper concrete mix and placement of it.
Good supervision , in your case strict supervision
Overall you have to be very proactive civil engineer on site .
As you only answer the question that cover blocks are provided to cover the reinforcement.
Why Cover blocks provided :-
Cover blocks are essential to protect the reinforcement from external weather conditions.For example, when rain water gets contact with steel it will slowly lead to corrosion.Due to these the still try to expand which ultimately leads to cracks on concrete surface and spalling of concrete begins.If proper cover is provided it will help to guard the reinforcement and its direct contact with water is minimised.
Your Case :-
As you said in your case reinforcement or bars exposed even after concreting so it is dangerous case as it will severely affect the strength of member as there will not be a proper bond between concrete and steel to transfer the stresses.
Yo must tighten the supervision or else take a strict action.
Cause of Problem :-
Sometimes due the less use of needle vibrators such honeycombs (voids) are observed after deshuttering.
There might be the chances that your mix is too dry (harsh) leading to such problem.
You must also ensure the water tightness of shuttering so that the concrete slurry shall not came out leading to seggregation of aggregates.
If the problem of honeycombs or voids continue even after adjusting or correcting the mix then it is desirable to pour 2 ghamelas cement sand mortar into columns just before concreting activity as suggested by one of the member here.