"although infrequently" is correct and usable in written English.
You can use it to concede that something only happens sometimes, but not very often. For example: "Although infrequently, I still enjoy going bowling on the weekends."
Although infrequently used with adults, it would not be considered offensive in most cases.
Although infrequently destabilizing, elections can create a focal point for mobilizing opposition, and political parties and legislatures can enable opponents to establish bases of support and provide a forum in which this opposition can coordinate.
Lung ultrasonography, although infrequently reported, also showed a positive association with educational status.
Although infrequently criticised in the early years, quality problems were evident, with poor trim and panel fit problematic for all first generation Commodores.
Several studies indicate that MRSA CC398 can be transmitted to humans as colonizer [11], [13], [17], [18], [19], and although infrequently reported so far, it is able to cause clinical infections [9], [20], [21], [22].
Haloperidol is used although infrequently as an antiemetic drug.
Although used infrequently during the wars, the flaming arrows and darts proved to be destructive.
The legal procedure that has been used - although very infrequently - to allow for the production of generic drugs for the treatment of AIDS is called a compulsory license.
Interestingly, numbing was also selected, although relatively infrequently.
Although used infrequently, some subjects did identify a numbing sensation occurring approximately 10 min after lingual administration.
