I don't want to focus on the "entire" history (https://tvtropes.org/pmwiki/pmwiki.php/ScrewedByTheNetwork/LiveActionTV) of the network because I figured that the infamous "Rural Purge" (https://tvtropes.org/pmwiki/pmwiki.php/UsefulNotes/TheRuralPurge) from the early 1970s would be an immediate "go-to" answer.

CBS (http://www.tvparty.com/80-1986-87.html) in their infinite wisdom, scheduled (https://saleintothe90s.tumblr.com/post/61355177403/91-melba-1986) the series premiere (https://www.latimes.com/archives/la-xpm-1986-01-28-ca-1069-story.html) of Melba (https://en.wikipedia.org/wiki/Melba_(TV_series)), a vehicle (https://books.google.com/books?id=70szDAAAQBAJ&pg=PA99&lpg=PA99&dq=melba+cbs+1986+challenger&source=bl&ots=ssTLwmzRgs&sig=ACfU3U2VEISzgNUFNAOksjC-bdEkyUm8RQ&hl=en&sa=X&ved=2ahUKEwiNv8Ty9er2AhUnnGoFHd4BA-Q4MhDoAXoECCYQAw#v=onepage&q=melba%20cbs%201986%20challenger&f=false) for actress-singer Melba Moore on January 28, 1986 (http://www.tvtango.com/listings/1986/01/28). Why is that date (https://www.nytimes.com/1986/01/28/arts/melba-moore-in-new-cbs-sitcom.html) significant, because it was the same day (https://boards.soapoperanetwork.com/topic/55820-stars-who-didnt-conquer-tv/page/2/) that the Space Shuttle Challenger disintegrated.

Inevitably, the premiere episode was as one of the lowest-rated (https://apnews.com/article/3a162af60668dd001a8b9a271271a44b) programs of the week (https://www.washingtonpost.com/archive/lifestyle/1986/02/05/the-tv-column/24ad6a42-5233-4c67-9471-21d5ecd1cc90/), and CBS (https://nostalgiacentral.com/television/tv-by-decade/tv-shows-1980s/melba/) immediately (https://books.google.com/books?id=U1Pe45NhU08C&pg=PA278&lpg=PA278&dq=melba+cbs+1986&source=bl&ots=mBBF6zb00O&sig=ACfU3U0PMhPhUAa3SlPy3OKdK_3ndBesqw&hl=en&sa=X&ved=2ahUKEwiFpaOU9er2AhXcmWoFHV1OABk4WhDoAXoECA0QAw#v=onepage&q=melba%20cbs%201986&f=false) pulled the show (https://www.portablepress.com/blog/2015/12/4-tv-series-cancelled-one-episode/) from its schedule (https://www.sun-sentinel.com/news/fl-xpm-1986-12-28-8603190159-story.html). The remaining episodes (https://www.paleycenter.org/collection/item/?q=lou&p=51&item=123025) were later aired (https://www.chicagotribune.com/news/ct-xpm-1986-08-02-8602250777-story.html) during (https://walkmemorylane.wordpress.com/2015/12/06/melba/) the summer.

9cZHZvWMa2I

Flo (spinoff of Alice) could have been sabotaged. Flo ranked #7 in the ratings during its first season, and even surpassed Alice in the ratings at one point! When the second season arrived, CBS moved the show around the schedule three times, making it hard for the viewer's to keep up with it. This caused a nosedive in the ratings, and Flo was cancelled at the end of season two.

TMC suggested Remember Melba?:

I don't think there is enough evidence to conclude the Challenger disaster was the reason or even a reason for the immediate failure of the series. The blackhole of the CBS schedule in 1985-86 was the 8-9pm Tuesday night slot. Up against The A-Team on NBC and the combo of Who's The Boss and Growing Pains on ABC, the Tuesday night 8-9pm slot on CBS was the place shows went to die. Here's a partial list of series scheduled in that timeslot during the 85-86 season:

1.Hometown

2. Stir Crazy

3. Charlie & Co

4. Trapper John M.D.

5. Morningstar/Evenstar

Plus various specials featuring Bugs Bunny and Daffy Duck among others.

Melba lasted one week, it wasn't the lowest rated show in this trainwreck timeslot, but it was in the lower range of all the shows that aired during the season in that timeslot.

Flo (spinoff of Alice) could have been sabotaged. Flo ranked #7 in the ratings during its first season, and even surpassed Alice in the ratings at one point! When the second season arrived, CBS moved the show around the schedule three times, making it hard for the viewer's to keep up with it. This caused a nosedive in the ratings, and Flo was cancelled at the end of season two.

I don't think Flo qualifies. Let's take a look at the history of the series.

Flo was number 7 the first season, but as they say the devil is in the details. The series replaced House Calls at the end of March after that series concluded its first season run. Slotted at 9:30 pm on Monday the lead-in was the monster hit MASH. House Calls was a hit and with the clear MASH connection (former MASH alumni Wayne Rogers was the male lead), the series would be returning to its regular time slot in the fall. In July, Flo was moved to its new time slot 8pm Monday night where it stayed through the end of January, a time period that covered the first 12 episodes of the new season. The show trended downward during the second season, after January it was moved to Saturday a less competitive night. The show continued to underperform, as a result it was canceled, and as they say, that's showbiz.

I have read that whoever high up at CBS didn’t like WKRP in Cincinnati for whatever reason and moved it around the schedule a lot. Probably stuck around as long as it did because it was an MTM Enterprises show.