The 2018 CARI paper concludes that China is not a big source of distress overall for Africa. It does not exclude that it might be for some African countries. The BBC summarized an earlier iteration of that paper in this respect:
In 2015, the China-Africa Research Initiative (CARI) at John Hopkins University identified 17 African countries with risky debt exposure to China, potentially unable to repay their loans.
It says three of these - Djibouti, Republic of Congo and Zambia - remain most at risk of debt distress derived from these Chinese loans.
In 2017, Zambia's debt amounted to $8.7bn (£6.6bn) - $6.4bn (£4.9bn) of which is owed to China.
For Djibouti, 77% of its debt is from Chinese lenders. Figures for the Republic of Congo are unclear, but CARI estimates debts to China to be in the region of $7bn (£5.3bn).
The same info is basically found in the CARI paper you have linked, in the last section of the table below:
Shadow's answer has given you the narrative version of what happened in Djibouti.
Clearly Pence is choosing to emphasize the most negative aspects of Chinese involvement in Africa. After all, the US and China are fighting an economic and propaganda war presently. And Pence has been remarked
as one of the hawks in this war.
Finally, if one focuses on the bigger picture of Chinese loans rather than just those that cause distress... resorting again to the BBC:
Around 20% of African government external debt is owed to China, says the Jubilee Debt Campaign, a charity which campaigns for the cancellation of poor countries' debt.
This makes China the largest single creditor nation, with combined state and commercial loans estimated to have been $132bn (£100bn) between 2006 and 2017.
That probably has the current US administration worried because it gives China influence in Africa, so I'm guessing they try reduce that in the cheapest way possible, which no doubt includes emphasizing the negative aspects in their speeches. The BBC points out another similar speech from Rex Tillerson, which did provoke a Chinese rebuttal:
Compared to institutions such as the IMF, World Bank and Paris Club (a group of 22 creditor nations not including China), loans from China are seen by some as much quicker, cheaper, and come with fewer strings attached.
The United States in particular has been highly critical of China's approach.
Earlier this year, ahead of a visit to Africa, the then US Secretary of State, Rex Tillerson, said China's lending policy to Africa "encouraged dependency, utilised corrupt deals and endangered its natural resources".
China's response was forthright. Its ambassador in South Africa, Lin Songtian, said China was proud of its influence in Africa and that Mr Tillerson's comments were part of a smear campaign by the United States.