Конечно, это неприятный момент, его придется учесть

Неправильный вариант: This is an unpleasant moment, which we will have to take into account.

Правильные варианты: This is a difficulty / problem / annoyance / irritant which we will have to take into account / with which we will have to cope / contend / which we will have to face.

Спад цен на эти акции – неприятный момент для нашей фирмы.

Неправильный вариант: The fall of the prices on these stocks is in unpleasant moment for our firm.

Правильный вариант: The decline / drop in the prices of these stocks is causing problems / difficulties / is a negative factor for our firm.