Sometimes for various reasons one could not continue to learn as actively as he/she wants and will drop the activity of learning almost entirely except for sometimes reading some lines in the target language to try to maintain his/her level. It is no doubt that if the learning is not done on a regular basis, the language skills will dwindle quite fast.
In the case where one has something like a limited proficiency level in that language (so that he/she can read almost everything with little troubles, I mean he/she can read quite accurately but reading can be slow at time compared to his/her native language).
Can doing a pause in learning be really disastrous? Would the language come again quickly when he/she would resume his/her activity?
Until now, the only experience I have about that question is that I used to learn Spanish and I was quite good in passive skills (oral and written comprehension), now, 5 years later I can still read Spanish (but not to my previous level, I would say that I can read B1 materials) but I could not speak a single word in it save for trifles.