Here it brings the following sources on the matter:
The Chasam Sofer (Shut Y.D. 341) was concerned about it and spoke about pushing off the learning until the coming Tisha B'Av.
Sefer Chassidim (261) is an interesting source. He says you should learn them because they aren't learned generally. So there you have the existing practice of not learning them except when needed, but the Sefer Chassidim not agreeing with it and regarding it as a neglected part of Torah.
R Shlomo Zalman Aurebach was not at all concerned about it, and found it surprising that these Halachos were not learned.
Kenses HaGedola (Y.D. 245:3) writes that the concern is only when it is part of a group study, however privately learning them is not a problem.