The Scramble for Africa occurred following the Berlin Conference of 1884-1885. Liberia was already an independent state by that time, however the Liberian state did suffer from territorial losses due to the provisions of the General Act of the Berlin Conference, specifically the Principle of Effectivity, which instituted a "use it or lose it" rule for the establishment of new colonies.

The Liberian government claimed control over large swathes of the hinterland and its tropical forests, but only effectively controlled the coastline. Consequently, and because it had no real military to stop European empires from incursions, Liberia was forced to cede parts of its territory to the British and French in 1907 and 1911.

tldr; in theory, Liberia already enjoyed state sovereignty. However, because it did not have true control over its claimed territories it did lose some land area to European powers.

The US Navy compelled the natives of coastal Liberia to sell land for former US slaves to settle on in 1821. Monrovia was fortified and suffered several attacks from local African tribes. More land sales were coerced and largely funded by American money and the state expanded. Liberia was recognized as a nation in 1847. It was ruled by former slaves from North America and not local tribes until 1980. So one can easily make a case that the indigenous Liberians did lose their independence to American financed former slaves and their decendants who were invaders backed at times by the US Navy.