How To Make A Mess Of French Conjugations

Each remark below applies to most conjugators, but few conjugators make all the listed mistakes. (I wonder how they chose which ones they will do.)
First, most of them present the French verbs as divided into 3 groups: the first, the second, and the third group. They do not bother giving you any criterium (except for -er verbs) that would allow you to know in which group to put a verb.
When they try, they travel blindly from spelling to pronunciation: the verbs in -ir would belong to the second group, and the verbs in -oir to the third one. But do not all verbs in -oir also end in -ir?

Second, they conjugate in "ghost tenses". The 2nd Past Conditional has never existed. To repeat the past-perfect of the subjunctive under another name is not enough to create a new paradigm. And anyway, what is this, the past-perfect of the subjunctive? It exists no longer, except in one fixed phrase, kept for fun. Some people try to use it, to make know how smart they are, but you can judge, from their mistakes, that they think they use the anterior past of the indicative.
Though not stinking as much as the past-imperfect, the imperfect of the subjunctive is dead; it hardly remains in written French, and only in the third person.

Third, they also conjugate "ghost verbs". Remordre might exist with the meaning: to bite again. But if it were the case, the conjugations would be "(le chien) remord, il a remordu, etc". What we read is: *il remorde, *il a remordé.
The funniest thing is that, above this "ghost verb" they warn: unknown frequency.
Ghost verbs conjugated in ghost tenses, there is a kind of logic.

Fourthly, when they conjugate existing verbs, they conjugate them mistakenly.
The verb ressortir (to fall within the juridiction) follow the same pattern as assortir: Nous ressortissons, nous assortissons. But conjugators prefer to follow the pattern of sortir and read: nous ressortons, which means "we go out again".
It is impossible to check each and all verbs, but in my opinion, the Guiness record should go to the Robert & Collins dictionary on DVD. It proposes to conjugate mourir with the auxiliary verb avoir: nous avons mort. I confirm: that's a killer!
I suppose that the person who created the first software, either was not a grammarian, or did not speak French, or hired someone at a cheap price and got a cheap result. The followers, brainless copists, copied the mistakes.
"You're sentence to check 500.000 conjugated forms!" Even the person who invented the conjugator did not deserve the punishment. How could he have checked thousands of verbs, conjugated in (roughly) 15 tenses x 6 pronouns? Nevertheless I cannot help wondering what would show up if I checked the whole thing thoroughly, instead of working randomly.
Whatever the reason that explains the presence of mistakes, here they are. Thus, do not rely on conjugators.
You can learn French verbs and French conjugations on your own; as I told you in a previous lens, it is not that hard. But choose the right tool to help you.