Mishnah Berurah — משנה ברורה

One should not recite the blessing - Since he moved them with the intent to replace them immediately. As opposed to when they moved on their own, we say that as soon they moved, the mitzvah "left", and that's why the Rem"a did not comment on what the Mechaber wrote there [in the previous part of this se'if]. You should know that the same applies if one removed his tefillin completely with the intent to put them back on right away - on that too the יש אומרים argues [and says one should not recite the blessing again], even if they moved to a different place in between. The Achronim ruled like this. If one didn't intend to put them back on immediately, but rather after some time - even if he ended up putting them back on right away; Or if one intended to put them back on immediately, but then it got delayed and he got distracted - All agree that he must recite the blessing again. Similarly, if one removed them in order to go the bathroom, even if he intended to put them back on right after, all agree that he must recite the blessing again since he is forbidden to enter the bathroom with them and they are pushed aside (ie. the mitzvah of tefillin gets interrupted since you have no choice but to take them off), as is written in siman 65. Chayei Adam wrote that the same applies when one removes his tefillin due to a need to pass gas, since it's forbidden to pass gas with them on, [therefore] once must recite the blessing again.