Vene has elections coming up. As a high yielder, it has been a historically popular range trade. Except now they have defaulted and been sanctioned. The leadership are linked to nacro trafficking (with Maduro's own family members imprisoned in the US for cocaine import) which along with oil linked patronage finances their leadership.
If the April presidential elections are taken badly by the US they could be classed as a pariah state with more sanctions and the bonds trade at 5-15c (from current mid-20s).
At some uncertain point in the future there will be a positive change, but that could be years away and when it does happen it will entail a huge debt haircut anyway.