Re: Problematic?
action (n) - something done
"activity, agility, alacrity, alertness, animation, bag, ballgame, big idea, bit, business, bustle, commotion, dash, deal, energy, enterprise, flurry, force, functioning, game, going, happening, haste, hoopla*, hopper, in the works, industry, life, liveliness, motion, movement, occupation, operation, plan, power, process, proposition, racket, reaction, response, rush, scene, spirit, stir, stunt, trip, turmoil, vigor, vim, vitality, vivacity "
behavior (n) - manner of conducting oneself
"act, action, address, air, attitude, bag*, bearing, carriage, code, comportment, conduct, convention, course, dealings, decency, decorum, deed, delivery, demeanor, deportment, ethics, etiquette, expression, form, front, guise, habits, management, mien, mode, morals, nature, observance, performance, practice, presence, propriety, ritual, role, routine, savoir-faire, seemliness, social graces, speech, style, tact, talk, taste, tenue, tone, way, way of life, ways, what’s done "
you do not see behaviour as a synonym of action yet action can be a synonym of behaviour (because a particular behaviour can be an action, while a particular action cannot be a behaviour; rather a set of (consistent) actions can collectively called a behaviour
“Similarly, he expired means the sa
me as he died, yet my passport has expired cannot be replaced by my passport has died.”
"Some lexicographers claim that no synonyms have exactly the same meaning (in all contexts or social levels of language) because etymology, orthography, phonic qualities, ambiguous meanings, usage, etc. make them unique. Different words that are similar in meaning usually differ for a reason: feline is more formal than cat; long and extended are only synonyms in one usage and not in others (for example, a long arm is not the same as an extended arm). "
hence you cannnot replace the word ‘action’ in some of the following sentences with ‘behaviour’ and make sense/keep the same meaning >>>>
"
[LIST]
-
He was critical of the government’s actions before the war.
-
a military action against another country
-
She tried to explain her actions.
-
I accept full responsibility for my actions.
-
The situation demanded immediate action.
-
The problem may require military action.
-
The school took disciplinary action against the drunken students.
-
They decided that no further action was necessary.
[/LIST]"
"
I’m surprised by her bad behavior toward her friends.
-
Students will be rewarded for good behavior.
-
scientists studying the behavior of elephants
-
An acceptable social behavior in one country may be unacceptable in another country.
-
Doctors are trying to educate people about behaviors that can put them at increased risk for skin cancer.
-
The experiment tested the behavior of various metals under heat and pressure.
"
behaviour – actions
if you read the webster dictionary rather than the dictionary.com, here are the synonyms for behavior
"Synonyms: actions, address, bearing, comportment, conduct, demeanor, deportment, geste (also gest) "
behaviour/behavior - w/e
for action -
“Synonyms: act, deed, doing, exploit, feat, thing”
ps i go to great extent to avoid such lengthly posts, 
but alas.
I hope this helps.
but alas.